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Pool Staining Problems

Stains and discolorations can be prevented and/or removed.
The Pool and Spa Informational Website

Causes, Solutions, Treatments and Suggestions.


Scroll down to browse through some archived SWIMMING POOL questions and answers.  Please click the Pool Topics Link, on top of every page, to access a complete listing of Pool Problem subjects, an alphabetized Website Table of Contents, Pool Equipment Information, About Alan Biographic Material and a Pool Glossary. Use the other links to access additional subject information. More information about some new and unique products, for pools and spas, can be found by visiting The Website Store. You'll never know what you'll find and that's always fun. Be better prepared and avoid costly problems!

Stain Reversall Kit. MetalTrap Filters for saving iron, copper and manganese problems. Dual-Cartridge Filter System.
POOL REFRESH eliminates phosphates and heavy metals. MetalTrap 1-Micron Pre-Filters, for Pools and Spas.
MetalTrap Stain Remover MetalTrap product can not only dissolve and remove metals stains, but they can permanently remove the metals, preventing a future recurrence, of the problem.  Use a MetalTrap to treat all new water.  Remove phosphates and sulfur too.  Staining and discoloration is not inevitable. Liquid MetalTrap

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How the treat and avoid pool staining and discoloration problems? Staining is a detraction from the overall appearance or aesthetics of the pool, as well as an annoyance. Colored stained walls, floors, steps and other underwater surfaces can result from the untreated presence of heavy metals, such as iron, manganese and copper, in the pool water. These metals can occur naturally in water (especially well water) or may have been introduced into the pool water, as a result of corrosion. Copper algaecides are usually in a chelated or stabilized form and are not normally a problem, when used properly as directed. However, the use of ionization products can result in the addition of too much copper and result in staining and or discoloration.  Pool stain and discoloration removal can be accomplished with the proper materials and techniques. The products, pictures above, will help you solve these problems.  New or freshly resurfaced masonry pools can be more susceptible to staining, until the underwater surfaces have "cured" and come to equilibrium with the pool water. Stain avoidance treatment should be considered, whenever a water analysis indicates the potential for a pool staining problem. If possible, test the source water before it is added to the pool, as it is best to add mineral treatments prior to the addition of oxidizers (chlorine, bromine or shock) or the pH and/or total alkalinity are increased. An alternative method of dealing, with pool water containing known heavy metal problems, is to use the METALTRAP Filter, which can physically remove the metals, as the pool water is being added. When the new water contains sediments, as well as dissolved metals, it is best treated with a METALTRAP Dual-Cartridge Filters, which keeps out both precipitated and dissolved forms of iron, copper and manganese. Other METALTRAP Products treat stain removal and prevention, phosphate removal and control of contaminants of all types.  If problems arise, refer to the Pool Problems Page, as a source of problem-solving information, broken down into various categories.  Scroll down the page and click on the linked keywords, catch phrases or images, in the archived answers below, to access additional information, on that topic or product.

Do you know what's in your water?  If you're having problems, with stains and discoloration, due to the presence of metals, you should be testing for iron, copper ad manganese, to better understand the extent and cause of the problem.  This helps select the best treatment option.  Understanding the nature of the problem, should be step one.  For information about our full selection of testing options, visit our Test Equipment Store.  For information about treatment options, visit our Stain Treatments Store.

There are many causes of stains and discolorations, which can appear in a variety of colors.
The color can sometimes point to a cause and solution.  Water Testing can help verify the cause of the problem.

Stain or Discoloration Color Cause and Treatment
Green or Brown

Most likely, these are organic, in nature, and are due to algae and/or tannins, leaching from many common varieties of tree leaves.  This is more likely to happen, if the sanitizer (oxidizer) levels are low and/or if there is poor circulation, across the pool floor.  Superchlorination and improving circulation, are the best course of action.

Dark Blue, Green or Black Dark blue, green or black colors or mixtures are likely caused by copper. High calcium hardness levels tend to cause the stains to darker, in appearance.  The source could be corrosion of the copper heat exchanger, natural sources, over use of copper algaecides, ionizer or mineralizers.  This type of problem requires proper chemical treatment, such as provided by the MetalTrap Stain Reversal Kit.  If present in the source water, a MetalTrap Dual-Cartridge Filter can be connected to the garden hose, used to add new water.  This will help prevent the addition of more metals, with each new water addition.
Green, Brown, Tea-Colored or Rusty-Red Green, Brown, Tea-Colored or Rusty-Red colors are usually indicative of an iron problem.  The most likely source is the water being used to fill the pool.  This is especially true, when well water is used.  While the use of a MetalTrap Stain Reversal Kit will help solve the problem, a MetalTrap Dual-Cartridge Filter should be attached to the garden hose, in order to avoid future recurrences.
Brown, Black or Purple Brown, Black or Purple colors are usually an indication of manganese being present.  This most often occurs, when well water is being used.  A test of the source water should confirm the presence of manganese.  While the use of a MetalTrap Stain Reversal Kit will help solve the problem, a MetalTrap Dual-Cartridge Filter should be attached to the garden hose, in order to avoid future recurrences.
Purple Purple stains or water discoloration can be due to manganese or the presence of copper cyanurate. Test the pool water, for the presence of both metals. While the use of a MetalTrap Stain Reversal Kit will help solve the problem, a MetalTrap Dual-Cartridge Filter should be attached to the garden hose, in order to avoid future recurrences.  Copper cyanurate can form, due to the prolonged use of stabilized chlorines.
Red or Blue Red or Blue Stains can be associated, with the presence of berries or vegetation.    This is more likely to happen, if the sanitizer (oxidizer) levels are low and/or if there is poor circulation, across the pool floor.  Superchlorination and improving circulation, are the best course of action.
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▼     Helpful, Problem-Solving Information, in a question and answer format.     ▼

Leaves Causing Pool Stains?

Hey Alan. We live in Louisiana and we have 10,000 gallon fiberglass pool. We do have Oak trees nearby and we now have brownish colored stains on the bottom, walls, and steps of the pool. We have treated it several times with metal away and we have used something that was a metal treatment. We have investigated and tried everything we possibly can and nothing has worked. If you can help us with this matter we would be eternally grateful. Thank you so very much.

Jill, Louisiana, 12/9/2017

Many types of leaves, such as live oaks or black olive & others, are more likely to cause problems. The leaves remainin
Water Sweeper Broomg in prolonged contact can release tannins and result in tea-colored stains. The good news is that tannins are destroyed by chlorine. All that should be required is a shock treatment and some bottom circulation. A Water Sweeper Broom can be an invaluable aid, in helping to keep leaves out of the pool.  It your source water contains tannins and organic matter, you can remove them using the MetalTrap 1-Micron Pre-Filter. It attaches to a garden hose and can be used to treat all new water being added to the pool.  Poor circulation can make chlorine distribution less efficient and make tannins removal more difficult. You might consider adding THE CIRCULATOR. The easy to install device will eliminate the dead spots that can promote tannin stains and algae growth. Helps to better distribute heat & chemicals and reduce filtration time.  I hope that I have been helpful. If so, please tell your friends and dealers about the website.  If this website was helpful, in solving your problem, please consider joining our E-Letter Mailing List.  You'll receive E-Letters, with helpful information, new product updates, suggestions and sale announcements. I am always glad to hear about a successful outcome.

Sincerely.  Alan Schuster, 12/9/2017

Pool Stains: Yellowish-Grey?

Thank you so much Alan. I found your website a year or more ago when I was still having trouble with metal in my water, but
Stain Reversall Kit. didn't take action at that time. Over several years my pool has built up an out of control level of metal in the water that has forced us to drain the pool four times last summer alone at the guidance of our local pool stores sadly enough. I was upset at the sight of our pool and thinking surely we will not be able to get it back in decent condition again. I was researching companies to re-surface the fiberglass, until I found your website yet again. I bought the METALTRAP liquid and stain remover and although I had to dose it twice to get the necessary results, it WORKED. I wasn't sure the yellow/grey stains were metal but it turns out they were and this product is by far the best I have come across. I have a white surface again with crystal blue water & my chemicals are perfect for the first time in years. So thank you Alan and I have ordered even more product to maintain my pool for the future. Wish I would have listened to my instincts the first time I found your site. God Bless!
METALTRAP Filters remove iron, copper and manganese.
Allen and Dawn S., 2/16/2018

About all I can add is that you consider using a METALTRAP Filter, to treat all new water, added to the pool. This will prevent,
iron, copper and manganese, from getting into the pool. With all that you have been through, this seems a prudent last step. All you have to do is attach it to the hose, used to fill the pool. Even if the water tests metal-free, if a fire hydrant is opened down the line, it can lift up sediments, that took years to collect.

Sincerely. Alan Schuster, 2/16/2018

Short Work Of Orange (Rust) Stains?

Alan, I have a iron issue in our pool from the well water top off. Came home from a long vacation to find an algae bloom in progress. Stupid me screwed up the chlorine level. Anyway, shocked the pool and thought metal magnet and clarifier
Metal Trap Stain Remover would help get the residue out of the pool. With the high chlorine level, I got an iron precipitate which left the pool surfaces a nice dark orange color. My local pool company recommended oxalic acid which I checked out on the web. Not nice stuff. I have been using your METALTRAP Filter to pre filter the well water to remove the iron for a while and checked your site. I knew about METALTRAP Stain Remover and have used it to remove some iron stains on occasion, but not to this extent. Bought your METALTRAP Stain Remover and waited until the chlorine dissipated, as directed. (Slow process since it is an indoor pool) Sprinkled in the pool stain remover and all the dark orange stain just vanished without the nasties of the oxalic acid. Didn't even lower the pH by much. Truly pleased with the product. By the way, the pool company had never heard that METALTRAP Stain Remover could do the job. Thanks again. A Satisfied Customer,

Jerry S., Fairborn, OH. 3/30/2016

Now that you have removed the pool stains, you should use the METALTRAP Filter to remove the stain-causing metals, by recirculating the pool water through the METALTRAP Filter. That way the problem will truly be solved. Use the METALTRAP filter when adding all new water and you'll keep metals out. Thanks for the letter.

Sincerely. Alan Schuster, 3/30/2016

Purple Pool Walls?

Gunite pool, pink algae year ago, used algaecide to get rid of it, and it worked, until it got warm. Then blue-purple color was on the walls, step walls (not on the bottom) of the pool. When got cold, went away. Now with it warmer, it's back. Water testing shows Calcium 600 (that is after 2 1/2 pool drains) chlorine is high, rest ok. Minerals - no iron. Pool people thought needs to be washed. Lowered water 1/2 way, and used liquid chlorine on the steps. What ever the chlorine touched that was purple TURNED BLACK! The towel I used to put the chlorine on turned warm. It did come off when brushed & some elbow grease. Questions: what is going on, besides a chemical reaction of some type? Should a chlorine wash get rid of this? We are selling the house and need to have it fixed for new buyer. Thank you.

Susan R., 5/2/2015

THIS IS DEFINITELY NOT AN ALGAE PROBLEM! IT IS DEFINITELY A MINERAL PROBLEM! The action of the chlorine turning the color from purplish to black is indicative of an oxidizing chemical reaction. A chlorine "wash" or shock treatment will probably be a waste of time and money. Purple pool water and stains can be indicative of manganese or possibly copper. It is not a common problem and most dealers do not test for it. If your water came from a private well, there is a greater likelihood that manganese could be involved. Another more likely possibility is copper. Copper in the presence of high levels of calcium hardness, which you do have,
Stain Reversall Kit. can cause dark or black stains, under certain conditions. The purple color could have been  due to copper, normally bluish in color, and the presence of cyanuric acid, from the prolonged use of stabilized chlorine products. When the pool people suggested a "wash", I suspect that they were referring to an acid wash. This type of treatment is periodically done on masonry pools to remove surface deposits and restore the look of the pool finish. It may be possible to remove the stains by chemical treatment. Try this. Put 1/2 pound of pH reducer powder in a white sock, shut off the filter and drop onto a stained area. Check after 15-30 minutes. If improvement is seen, this would be indicative that chemical treatment might work. Chemical treatment will require that you add 2-3 doses of a quality, phosphate-free metal treatment, such as Liquid MetalTrap, to help prevent further pool discoloration. Raise the pool water level above all of the discoloration and staining. Add muriatic acid until the pH has dropped to 6.8. It may take considerable acid, depending upon the starting pH and the total alkalinity. Without the lowering of the pH, you are not likely to remove the pool stains. Add MetalTrap Stain Remover, which acts as a reducing agent, converting the metals to a more soluble form. Combined, these products form the basis of the MetalTrap Stain Reversal Kit. This can help in removing the stains and can be added to the acidic pool. This material will react with chlorine, so add only when the chlorine level is very low. At that point the addition will zero out the chlorine and create conditions more favorable for pool stain removal. Use the brush to help things along. Metal parts in the pool, pump and filter may be affected by the acidic conditions. Clean or bypass the filter, if possible, to remove stain causing debris from the filter. Depending upon the pH, you should see improvement in a day or so. Once the pool stains are removed, add another 2-3 doses of a quality mineral treatment, before restoring the pH. It will be necessary to shock the pool, in order to destroy all of the stain remover and reestablish proper pool chemistry. Where did the copper come from? If you have a heater you may have subjected it to corrosion. Copper algaecide is another possibility. I hope it works out for you.

Sincerely. Alan Schuster, 5/2/2015

Thank you Alan. Yours has been the first sensible response I have had. It does come off with the sock and sodium bisulfate. Took no brushing. We cannot bypass our filter. Can we lower the pH, then bring it back up and still have swimable water? Thank you again.

Susan R., 5/2/2015

The purpose of the bypass was to minimize corrosion. Clean the filter out before treatment an
METALTRAP Filters remove iron, copper and manganese.d again afterwards, so as not to redissolve what you are trying to remove from the pool walls. Don't neglect to add the Liquid MetalTrap! Otherwise, you could get a recurrence. You can swim as soon as you restore the pH and the chlorine levels. Inasmuch as the pool stain was removed without the ascorbic acid, I don't see the need to add the product. It seems that things will work out for you. The METALTRAP Filter is a non-chemical means of removing metals from the water. just attach to a garden hose and a small pump and keep recirculating. The longer you recirculate, the more metals are removed. Use it to treat all new water and you'll avoid pool stains and stay in the blue. Good luck with the sale of the house.

Sincerely. Alan Schuster. 5/2/2015

Acorn And Leaf Pool Stains?

Our 72,000 gallon community pool was resurfaced last year: the good news. The bad news-those in charge did a poor job covering the pool and a lot of leaves got in the pool, sat there, and stained a few large areas of the surface. I tried 4 lbs of Stain Wipe, a concentrated ascorbic acid powder, which removed only 50% of the stain. Should I try the sock with the pH lowering chemical? Thanks.

Bert S., 10/27/2014

Acorns and many types of leaves, such as live oaks or black olive, are more likely to cause staining problems. The acorns, leaves
The Circulator for all types of pools. and plant debris, remaining in prolonged contact, can release tannins and result in tea-colored pool stains. The good news is that tannins are destroyed by chlorine. All that should be required is a shock treatment and some bottom circulation.  Ascorbic acid was not a viable solution, for this problem, as it should only be used to remove pool stains caused by copper, iron, manganese or other heavy metals.   Poor bottom circulation, may lead to a lower chlorine level across the lower part of the pool. Using a robotic pool cleaner on a regular basis will help improve the circulation and remove the leaves that might lead to pool staining. Weak overall circulation and dead spots can add to this type of problem. THE POOL CIRCULATOR is a device that greatly improves circulation. It installs in the return fitting quite easily. I hope that this information will prove useful.

Sincerely. Alan Schuster. 10/27/2014

Huge Black Pool Stains?

Alan, I just decided to open my pool for the summer. Unfortunately I do not have a lot of time to care for it myself so it sat all winter without a cover. I live in Ft Worth TX so temperatures stay pretty warm most of the year. I have huge oak and maple trees in my back yard and their leaves fell in the pool and decomposed. I had a service empty the pool and acid washed it but they are TONS of huge black stains at the bottom of my pool. I have a 30,000 gallon gunite and plaster pool and the plaster is wearing off. The pool is at least 15 years old, and I have lived here for 3 years. Is there something that can remove these stains or should I just re-plaster the pool? I think I am getting a fair deal on the replastering, so I am considering it. Thanks.
Randall, Ft. Worth, TX, 6/5/2013

It does appear that you will be refinishing the pool sooner rather than later. There's little sense investing a lot of time and money, but it still might be a good idea to clean up the pool. It might make for a better plastering job? Most likely the pool discoloration and stains are the results of tannins from all of the leaves, especially the oak leaves. Boost the Free Chlorine level to 5-10 PPM
and keep it there for a day Stain Reversall Kit.or so or until the stains disappear. Adjust the water chemistry as necessary and keep the filter operating. This should do the trick and you'll be in a better position to determine when to resurface the pool.  If pool stains resist the chlorine treatment, they are most likely caused by metals. Just adding Liquid METALTRAP and METALTRAP Stain Remover may remove the stains, but it might not be permanent. If you use the MetalTrap Stain Reversal regimen, you'll remove the pool stain and remove the metals, as well. You start by adding the METALTRAP Stain Remover, as directed. This helps dissolve the stain. Next Liquid METALTRAP is added, to complex or chelate the metals, in order to keep them in solution. Next. you recirculate the pool water through a METALTRAP Filter and those heavy metals will be permanently removed. In you plan on refinishing the pool, ask the contractor to add water to the plaster, after it has been run through the METALTRAP Filter. If might help prevent the pool finish from slight discolorations. By all means, when the pool is refilled, pass all the water through the METALTRAP Filter. Removing metals, as the pool fills, is the best insurance against future problems. Remember, always use the METALTRAP Filter to treat all new water.  The new pool finishes today can be quite different from the one used in your pool. It is not just plain old plaster any more. There are all types of finishes, with different looks and properties to consider. Good luck and I hope that I've been helpful.

Sincerely. Alan Schuster, 6/5/2013

How to deal with metals, stains and contamination.

These products remove metals and avoid future, recurrent problems.
Don't just treat stains . . . eliminate them and prevent their return!!!
Stain Reversal Kit. Liquid MetalTrap MetalTrap Stain Remover. Pool Refresh eliminates phosphates and metals, from pools and spas.
Metals Stain Removal Kit Liquid Metal
Chelating Agent
Stain Remover
Eliminates Metals and Phosphates
MetalTrap Dual-Cartridge Filter, for pools and spas. MetalTrap Single-Cartridge 5-Micron Filter System, for pools and spas. MetalTrap Filtesr remove heavy metals. MetalTrap 1-Micron Pre-Filter, for Pools and Spas.
Dual-Cartridge Filter System 5-Micron Single Cartridge Filter System Filters for Heavy Metals Removal 1-Micron
Visit The Metals and Staining Treatment Store for complete information.

How Does The METALTRAP Work?

I do not understand how the METALTRAP Pre-Filter works to filter the water that is already in the pool. Do you install into the existing filter, pump plumbing? I have treated the pool on several occasions with 100% ascorbic acid and a metal treatment, but the stains come back a couple weeks later. Some metal treatment degrade over time, causing a recurrence of the problem and adding phosphates to the water. Liquid METALTRAP is more stable and contains no phosphates. Thanks!

Tom M., 8/18/2017

Just get a small pump or submersible pump with garden hose connections.  Attach to the METALTRAP 1-Micron Pre-Filter and pass
water through the filter and back into the pool. Slowly it will trap the metals in the pool water, reducing the level, as time goes by. It only process 5-7 gallons a minute, so it will take a while to turn over the pool water, a few times. But, in the end, the metals are out of the pool and the recurrence of pool stains should be gone. Use it to treat all new water, added to the pool, to help keep them out. Some metal treatment degrade over time, causing a recurrence of the problem and adding phosphates to the water. Liquid METALTRAP is more stable and contains no phosphates. I hope this will make things a bit clearer.

Sincerely. Alan Schuster, 8/19/2017

Grass Seed Stains?

While spreading grass seed on the lawn some of the seed got in the pool and left a rather large brown stain down the side of the pool wall and down towards the bottom , we just had the pool plastered 2 years ago, how do I get the stains out Help me please.

Michael S., Bakersfield, CA, 4/3/2012

Regular grass seed should not do that. Some seeds are coated with fertilizer and mulch to help it germinate. The minerals in the fertilizer could cause this type of problem. The information below should be helpful. However, the solution could be as simple as shutting off the pump and sprinkling some METALTRAP Stain Remover and letting it sink over the pool stains. It will work best without any chlorine present. Follow with a dose of phosphate-free Liquid METALTRAP, to deal with the dissolved metals.

Place a dozen 500-mg Vitamin C (ascorbic acid) tablets on a stained area. If it removes the pool stain, the directions below will treat the whole pool. In the vast majority of cases, merely adding a metal treatment will not remove the stains., especially when covering large areas. A reducing agent, such as METALTRAP Stain Remover must first be applied, at the dosage rate of 1 pound per 10,000 gallons. Before applying, the free chlorine, must be allowed to drop to 0 PPM. otherwise, the chlorine will destroy the stain remover. Chlorine neutralizer can be used to quickly drop the level.

Allow the water, containing the METALTRAP Stain Remover to circulate 24/7. Brush the surface to help speed the process.  After the stains are gone., do one of the following. Either add 1 quart of Liquid METALTRAP, per 10,000 gallons of water, for each 1
METALTRAP Filters remove iron, copper and manganese. PPM of metals present. Test the water for metals, to better understand the extent of the problem. Alternatively, you can use a small submersible pump (flow rate of not more than 5-8 gallons per hour) and recirculate the pool water through the METALTRAP Filter. This will remove the metals, that the stain remover dissolved from the walls. A METALTRAP Filter uses garden hose connections and can remove up to 1 PPM of metals, based on its rated capacity. If you use the METALTRAP Filter, when adding all new water, you can keep more metals out of the pool. It may take several days, with the submersible pump running 24.7, to get the levels down to a manageable point. Again, test the water in the pool and coming out of the METALTRAP Filter to monitor the progress. At the point, where the metals are down to a nil level, add a dose of liquid METALTRAP, to scavenge up the last traces. Wait 24 hours before adding chlorine or raising the pH. A lot of chlorine will have to be added, because it will react with the pool stain remover. Because the process can get lengthy, it is a good idea to add a dose of a polymer algaecide, to help maintain water quality, in the interim period.  I hope that I have been helpful. If so, please tell your friends and dealers about the website.

Sincerely. Alan Schuster, 4/4/2012

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Fertilizer Stains In Pools?

We recently fertilized our yard, and accidentally got some in our inground pool. The rust stains are scattered throughout the pool. We called our pool company, and they suggested adding ascorbic acid, which we did, but to no avail. Is there anything else we can do to fix this problem?

Jon G., 4/2/2016

The pool stains that resulted are due to iron and other trace minerals, that are present in the fertilizer. If you simply added the ascorbic acid to the pool, it is unlikely that anything beneficial will result. The chlorine could have destroyed the ascorbic acid, before it contacted the pool stains. Try this. Add 1/2 pound of pH reducer powder to a white sock, shut off the filter and drop onto a stain. Position using the vacuum pole and leave in place for 5-10 minutes. Move the sock around with the vacuum pole after this period. If the pool stain is gone, repeat elsewhere, as needed. If this fails, try the same thing with some METALTRAP Stain Remover, in the sock. Once the stains are gone, add a dose of quality metal treatment, such as Liquid METALTRAP, in order to avoid a recurrence.  I hope that this information proves helpful.

Sincerely. Alan Schuster, 4/2/2016

Vitamin C Treatment In Pools?

Hi Alan, I searched your site for references to treating stains with vitamin C and couldn't find anything. I have an inground fiberglass pool that came with a house I purchase several months ago. The pool began getting stains and with help from my local pool water testing company tried unsuccessfully to get them out. I tried algaecides, etc, and metal stain removers and nothing worked. My water tested negative for iron and copper. Someone mentioned to me to use vitamin C and I noticed the original pool/house owner had bottles of vitamin C stored away and I said well maybe he used that - which made no sense to me. I tried it and bam, the stains vanished almost immediately. What in the world? Can you help me understand this? What were the stains and why would vitamin C of all things work? Thanks!

Sonny M., Wake Forest, NC, 6/4/2009

If the problem is a pool metal stain, adding algaecide or shock is useless. Adding a metal treatment, without creating mildly acidic
conditions, rarely works. The vitamin C tablets worked because it is an acidic, reducing (antioxidant) agent and you were able to put it right oStain Reversall Kit.n the pool stain. METALTRAP Stain Remover has been formulated, for use in treating stubborn metal stains. If an entire pool needs to be treated, all of the chlorine should be discharged, the pH lowered to about 6.8 and then the ascorbic acid is added. Fiberglass pools can attract metallic ions and chemical treatment is not necessarily the same as removal. The METALTRAP Filter actually, physically removes the metals, from the pool, as the water is recirculated through the Metal Trap. Using the METALTRAP Filter to treat all new water helps keep new metals out and minimizes the possibility of staining. Liquid METALTRAP and METAL TRAP Pool Stain Remover should be used, in conjunction with the METALTRAP Filter to first remove the pool stains from the underwater surfaces and, finally, to remove the metals from the pool. These product contains no phosphates or use toxic oxalic acid. The important thing is that there is a plan that will work.  Enjoy the season.

Sincerely. Alan Schuster, 6/5/2009

Treating Metals Without Adding Phosphates?

Recently, I added some metal treatment to my pool, to control a trace level of iron. All seemed to go well. No staining and discoloration. I wasn't sure that I really needed the product, but better safe than sorry? A month later, I brought in a water sample to have a mid-season check done. I was told that I had 800 PPB of phosphates. So I questioned the source of the problem and was told that it probably came from the metal treatment. I looked at the label and it stated that it contained "Organic Phosphonic Acid." Now it seems that I traded one problem for another. Was there an alternative?

Henry H., 7/19/2009
Liquid MetalTrap.

Yes, there was an alternative! Liquid METALTRAP contains a completely different active ingredient and is phosphate-free. In fact,
it reacts with metals and resists degrading, over time, which is what causes the other product to form phosphates and allow a possible return of the original problem. In your case, it was only a trace and may have gone unnoticed. On the other hand, the formation of phosphates can allow algae to grow faster, especially, if the free chlorine level is low. It is possible to treat for phosphates, but one should question was it avoidable? Liquid METALTRAP would have solved the initial trace metal problem, without adding any phosphates.  I hope that you have been enlightened. Enjoy the season.

Sincerely. Alan Schuster, 7/20/2009

Rusty Nail Pool Stains?

Your website has a most amazing amount of information, but does not appear to cover our specific problem. We bought the house to do a major renovation. During construction we had the pool (vinyl liner) covered but much debris got onto it anyway. After cleaning out the pool we are left with quite a few rust spots on the bottom of the liner, probably from nails among other things! Do you have any suggestions as to how to get rid of the rust? Thanks so much.

Nancy, White Rock, BC, Canada, 5/19/2009

The information was there, but not spelled out in terms of a rusty nail. It happens a lot, so I will add it. Place a few vitamin C (ascorbic acid) tablets on a stain, shut off the filter and leave in place for 15 minutes. If this worked, put a handful of 500-mg Vitamin C tablets, in a white sock and drop onto a stain. Slowly move around with a wooden pole. Sometimes, just using pH reducer granules, in a sock, will work, so you might try that first. I hope that this information will solve the problem. It should!

Sincerely. Alan Schuster, 5/19/2009

Working Stain Removal Scenario?

A Staining question for you. We have an inground 45,000 litre pool with a vinyl liner. We have been getting a yellow/gray discolouration on the vinyl liner (bottom and sides). We thought it was algae but chlorine seemed to have no effect. I then tried METALTRAP Stain Remover in a sock and after about 30 minutes, about a 4' diameter area in the deep end (where I laid the sock in) was nice and bright again. Will this scenario work?

1) Neutralize the Chlorine or allow to fall to nil.
2) Lower the pH to 7.0 to help eliminate the stain
3) Add METALTRAP Stain Remover to help treat the minerals/metals
4) Add Liquid METALTRAP, after stains are removed.  Wait at least 24 hours, before proceeding further.
5) Raise the Chlorine level.  It will take a relatively large amount, so add in increments.
6) Adjust the balance of the chemicals.
7) Add a dose of Liquid METALTRAP monthly.

Is this the right methodology? Thanks.

Dennis, Canada, 5/2/2007
METALTRAP Filters remove iron, copper and manganese.

the very least add two doses. If the stained area is too broad to be treated with the "sock", you may have to lower the pH of the pool to 6.8, discharge all of the chlorine and add a few pounds of MetalTrap Pool Stain Remover. Thereafter, add a dose of Liquid METALTRAP monthly or prior to adding new water, in order to avoid minimize the possibility of a recurrence. Even better, use a METALTRAP Filter to treat all new water. I hope that I have been helpful.

Sincerely. Alan Schuster, 5/2/2007

The Source Of The Pool Staining?

Many thanks for the Metal Trap Stain Reversal Kit which has arrived safely here in France. I am currently battling away to achieve the right chemical balance before using it. The cyanuric acid level was as high as 140ppm and I am seeking to reduce it by part emptying the pool and then re-filling as you suggest. The pH at 7.6, I will lower to your recommended level, whilst the chlorine is currently at zero after my emptying and re-filling processes. Should I add some chlorine before using the kit? An analysis of the pool water has established that the iron content is less than 0.1 PPM! This is making me wonder whether the staining has in fact been caused by metals and if not, whether the stain removal kit you have sent me will prove effective? Can you envisage any other cause for the staining? As mentioned previously, a test with a Vitamin C tablet did prove effective. Does your stain remover contain ascorbic acid as it seems this is what is required? The only other bit of info. which may be relevant is that the local water board did some work last year on the supply pipes in this area. I would be most grateful for your replies to the above questions and for any further advice in general. With all best wishes and thanks for help to date.

Mick P. France

There is a paradox, with metal pool stains. If the metal has stained the walls, it is no longer in the pool water, at the original concentration. Therefore, getting a low reading, does not mean that metals were not present, at some time, and caused the pool stain. If Vitamin C made a difference and removed the stain, where it was placed, it is most certainly a metals problem and METALTRAP Stain Remover. Your CYA level does need to be lowered, by replacing water. Use the METALTRAP Filter, to treat all replacement water. Water Supply Companies working on underground pipes, tend to lift sediments off the bottom of the pipes, that may have been accumulating for years. That could very well be the source of the iron. You want the chlorine level to be zero, or else the METALTRAP Stain Remover will be destroyed, to some extent, by the chlorine. Adding a dose of 60% polymer algaecide will help maintain the water quality, during the treatment process. Good luck and I hope things clear up.

Sincerely. Alan Schuster, 9/17/2009

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The Swimming Pool Blues?

Just want to get a head start on this years pool season. Last July our Alkalinity. was low so we were told by our local pool store to put alkalinity plus into our inground pool (32000 gallons give or take). Within 24 hours we had a blue stain throughout the pools liner. on the walls and steps etc. It even stained our son's scalp blue. Our pool store, that sold us the alkalinity plus said this is common when you raise the alkalinity (used 50lbs) as much as we had to. I put a ton of stain remover in the water and it cleared up around August. Is this blue stain common when you raise the TA in a pool? We use a well, that might have some iron, but it never positive tested for copper.

Wondering, 1/18/2016

Such a thing will only happen, if there is copper present. It seems likely that your pH and TA were low for an extended period of time and that you have a heater. This corrosive chemistry caused some copper to dissolve from you heater or copper pipes.
Stain Reversall Kit. When you raised the pH and/or TA, it precipitated. You would have been better off adding a metal treatment first. From now on I would add a dose of a metal treatment monthly and avoid low pH conditions. Proper TA is part of that. There is a better solution: the METALTRAP Filter actually, physically removes copper, from the pool, as the water is recirculated through the METALTRAP. Using the METALTRAP Filter to treat all new water helps keep new metals out and minimizes the possibility of new pool staining. Liquid METALTRAP and METALTRAP Stain Remover should be used, in conjunction with the METALTRAP filter to first remove the pool stains from the underwater surfaces and, finally, to remove the metals from the pool. These product contain no phosphates or toxic oxalic acid. If you use trichlor in a feeder, it must be last in line and separated from the heater by a check valve. Otherwise, corrosive solutions can backup into the heater, after the pump is shut off.  I hope that this information will help you understand what transpired.

Sincerely. Alan Schuster, 1/19/2016

An Ionization/Staining Conundrum?

Great site! I have a 25000 gal gunite pool that is two years old. The previous owners used chlorine and last year I switched to an ionizer/oxidizer. Toward the end of the summer I started to get brown-black staining of the bottom. I have a problem with the pH constantly creeping up. What is the best way to remove the mineral stains and use the ionizer/oxidizer? How long should I use the oxidizer every day? One turn of the filter is 4 hours. We do have a well, which might have some iron present. The previous owners never mentioned that it was a problem. Thanks.

Dr. Ed S., 3/8/2009

The pool stains could be the result of iron, manganese or other heavy metals that might have been present in the well water. You should test both the pool and source water for heavy metals. The sanitizing system that you are using
seems to be one that utilizes copper ions and oxidation. Too high a copper level, especially in the presence of high calcium hardness and high pH, can cause dark pool staining. Testing the pool for copper can determine if the level is too high. Dealing with the copper, iron or manganese or pool staining usually requires metal treatmenMetal Trap Stain Removerts and that could temporarily eliminate or limit the algaecidal function of the copper. However, there is an effective way to approach this problem. Allow any free chlorine to zero out and turn off the ionization unit. Add a quart of 60% polymer algaecide to maintain the water, while there is no oxidation present. Get the pH to about 7.0. Now add METALTRAP Stain Remover and keep the filter on 24/7. Scrub the walls, to help things along. In due course, the pool stains will be removed.  There are two choices to make, at this point. You can use the cartridge-like, METALTRAP Filter with a garden hose and a small submersible or cover pump and recirculate the pool water. As the water passes through the METALTRAP Filter, the heavy metals, including the copper, are trapped and removed permanently. Or, you can add Liquid METALTRAP to the pool and that will chelate the metals. The metals will still be in the water, but in a solubilized state. They may still register on tests. If you use the MetalTrap Filter instead, it may take a few days, but if you test the water, you will see the iron and copper levels (in your case) dropping. Once the iron level gets down to under 0.05 PPM and the copper level is under 0.3 PPM, you can restart the ionization unit. Add chlorine, to destroy the remaining METALTRAP Stain Remove, until you get a free chlorine reading that lasts through the night. From this point on, operate your pool in the usual manner. The iron was removed, by the METALTRAP Filter. It also took out some of the copper, but that can be replaced. Use the METALTRAP Filter to treat all new water added to the pool. I hope that this information will provide you with an easy way out.

Sincerely. Alan Schuster, 3/8/2009

Reverse Side Stain In Vinyl Liner Pool?

Alan: I have a medium size stain in the deep end of my pool. It is dark looking and appears only to be in one spot. I had a new liner installed two years ago. The local dealer said it was a problem that sometimes arises under liners, because the government banned a certain treatment that companies were using on the liners before installation. I have a 20x40 pool and use chlorine. The locals said to try a chlorine tablet inside panty hose and let it set on the spot up to one minute. This did not work. Now they tell me to treat the surrounding soil with ferrous (iron) sulfate to change the soils pH. The pool tech said this was a new treatment and has worked on some stains. Have you heard of this and do you think this might work? These are reputable businesses and I have done business with them since buying this property ten years ago. Please advise? I live in Decatur Alabama. Thank you.

Daryl G., Decatur, AL, 1/25/2005

I have heard of this treatment. I believe that the premise is based on treatments used in landfills. Ferrous (iron) sulfate is added to the ground around the perimeter of the pool. If it works, it is not because it is acidic. If that were the case, there are better acids to add. Ferrous sulfate is a reducing agent, that will react with oxygen containing products. The theory is that it creates an oxygen reduced zone, as it diffuses under the pool. The stains are probably being caused by the growth of certain molds or fungi. Treatment with the chlorine tablet in the panty hose, will only serve to bleach the liner. It will not work on a problem that exists on the reverse side of the liner. You have nothing to lose by trying this ferrous sulfate treatment. Make sure that none of the chemical gets into the pool water or else pool staining and pool water discoloration will result. Please let me know how it turns out, as I will share this information with others. I have no information on any recently banned treatment. Good luck and I hope that I have been of some help.

Sincerely. Alan Schuster, 1/25/2005

Using Ascorbic Or Oxalic Acid?

I have tested the two options that you have recommended and the one that works best is the Vitamin C. It works very smoothly, no damage to the finish and cleans almost completely the stains Only a little shade remains, but it's not very noticeable. Now I suppose I would have to move to the acid for the other stains. Which one should I use, oxalic or ascorbic acids, and how do I apply it? Are they expensive? Would another option be to continue using the vitamin C? Once again your help is highly appreciated. Before I got your advice, I tested unsuccessfully a test kit for stains and a treatment product, which didn't work and eroded the finish. Have a great holiday season. Best regards.

Gustavo B., 12/21/2008

PS All my friends and my pool service guy already know about your site!

Your already know that vitamin C will work, so MetalTrap Stain Remover is the product that I would recommend. It is not inexpensive, but is by no means prohibitively costly. Most people shy away from oxalic acid, because it is toxic. If MetalTrap Stain
METALTRAP Filters remove iron, copper and manganese. Remover works, it is less expensive than products that don't perform satisfactorily! To help get the best effect, allow the chlorine level to drop to near zero. If you are dealing with limited areas, as is the usual case with fertilizer stains or a foreign object, put some in a sock and drop onto the stained area. Slowly move around with a pole. To treat the entire pool, broadcast the product over the surface. If the filter is off, it may reach the bottom, in greater strength. It won't damage pool finishes. Start the filter running, after about 1/2 hour. Once the pool stains are gone, add a dose of a quality, phosphate-free metal treatment, such as Liquid MetalTrap and wait 1-2 days, before restoring the chlorine and pH levels. Enjoy the holidays - stain free hopefully.

Sincerely. Alan Schuster, 12/21/2008

Using Ascorbic Acid In A Pool?

First off, great site. You have been the only person that has steered me in the right direction. My wife and I bought a house last year and opened the pool for the first time (2003). The pH level was unreadable (very low). After about 1.5-2 weeks we were able to get it to 7.2 (don't even ask me what the previous owner did). Mid pool season last year we noticed some purple and tan staining. We spoke to pool places, but they were no help. This year we were told it may be metal, so we tried a metal out product. Nothing. Then we finally got directed to your web page from a pool message board. This evening I took a Vitamin C tablet, and sure enough, I was practically able to draw in the stain. The bright blue liner popped right through. So now that I know I have to get some ascorbic acid, drop Cl and pH way down, I have a question. Since the vitamin C took it right off without messing with the Cl or pH, why couldn't I put some ascorbic acid in a sock the way the chemical level is now and scrub the stains, then add a metal remover? Would the stains be harder to remove? Or would the pool stains, I am removing, float through the water and stain other areas? Again, thanks for your website, my wife and I are so anxious that we may now be able to have a nice looking liner.

Greg O., 6/10/2008

You could put ascorbic acid in a sock and run it across the bottom. The problem is that chlorine will destroy ascorbic acid and that is why I suggest dropping the chlorine level to zero. The vitamin C tablet is useful to determine if the treatment, will work. If the whole bottom and/or walls are stained, the sock trick may prove difficult. I would lower the pH to about 6.8, discharge all the
Stain Reversall Kit. chlorine by adding chlorine neutralizer and then follow with ascorbic acid, using the label dosage recommendations. Add MetalTrap Stain Remover, at the dosage rate of about 1-pound per 10,000 gallons Once the pool stains are removed, add a dose of a quality, phosphate-free metal treatment, such as Liquid MetalTrap. This is important to help avoid a recurrence. Have your tap water tested. If iron is present, add a dose of metal treatment monthly and prior to any new water being added. There is a another solution: the METALTRAP Filter physically removes iron, from the pool, as the water is recirculated through the Metal Trap. Using the METALTRAP, to treat all new water, helps keep new additions of iron and other metals out and minimizes the possibility of pool staining. Liquid METALTRAP and METALTRAP Pool Stain Remover should be used, in conjunction with the METALTRAP filter to first remove any stains from the underwater surfaces and, finally, to remove the metals from the pool. These product do not contain phosphates or use toxic oxalic acid. I'm glad the you found the website. Enjoy the season.

Sincerely. Alan Schuster, 6/10/2008

Oxalic Acid Effect On Pool Chlorine?

My pH at this point is only slightly low. What I'm concerned about now is I used the pool today and tested after use and there is a VERY low chlorine level. How can that be? I just shocked the pool 2 days ago. I just put 2 tablets in the skimmer and am letting the pool run now. The water is clear and blue. (I also have a UV sterilizer connected to this pool.). But I'm just shocked that the chlorine level went down so fast. Maybe consuming all the algae really depleted the chlorine? Or, do you think my using the oxalic acid used for the step stains effected the chlorine level?

Pat T., 4/10/2007

Oxalic Acid reacts with chlorine. That is why you want the chlorine level low to before addition. After the pool stains are removed and metal treatment has been added, you must keep adding chlorine, until a stable 1-3 PPM level is established. Enough fast dissolving chlorine has to be added to destroy both the residual oxalic acid and any remnants of algae or organic waste. Once this is done, it should be easier to maintain. Handle oxalic with care, as it is toxic. I hope the information is helpful.

Sincerely. Alan Schuster, 4/11/2007

Yellowish-Brown Pool Stain?

Alan, I came across your website from the Aquatics International magazine. I have had a staining problem for a couple of years that maybe you can answer. I operate two indoor, commercial pools. One is a 110,000 gallon recreational pool, the other is a 300,000 gallon competitive pool. The recreational pool has a yellowish-brown stain on the bottom of it. I have tried scrubbing with metal brushes and other tools with no luck. Last year we drained the pool completely and acid washed the bottom which did get rid of the pool stains but they have come back. We use calcium hypochlorite for sanitation and muriatic acid to lower pH. We keep the temperature in the recreational pool at 85-87 degrees and the temperature in the competitive pool at 80 degrees. For some reason I do not have a problem with staining in the competitive pool. I have never checked for levels of iron or copper. Do you know what is causing this stain? Thank you for any input.

Kevin B., 1/18/2008

It is difficult explain why only one pool is experiencing this problem, especially if the chemicals are the same and the materials of construction are similar. The only thing that comes to mind is that they were filled at different times - one after the other - and
METALTRAP Filters remove iron, copper and manganese. this introduced sediments, that were lifted off the bottom of the pipes. Your description and the fact that the pool stains are removed with acid washing, suggests the problem is metals. Iron would be the most likely. Copper can produce blue pool stains and, in the presence of high calcium hardness levels, can produce dark pool stains. Manganese can be present in some well water and produces dark pool stains. I suggest that you have the pool water and source water tested for iron, copper and manganese.  Metals problems can be avoided by the prior treatment of the pool with appropriate, phosphate-free chelating agents, such as Liquid MetalTrap or the use of a metals remover filter, such as the METALTRAP Filter. Even if no metals are detected, I would add a dose of Liquid METALTRAP now and additional product prior to adding new water. I hope that this information helps to explain the mystery.

Sincerely. Alan Schuster, 1/19/2008

Tannin Stains: Maybe Yes - Maybe No?

Hey Alan. Far and away, yours is the best site I have seen on stain removal. I have looked through all of the suggestions and I am hoping you will clarify a couple of things for me. I have reddish-brown stains that are all in the area of where leaves deposited themselves, so I am 90% sure they are stains of the tannin variety. I have read where you suggested a chlorine ratio of 5 ppm to get rid of the stains. The thing is that I have a salt chlorinator for my gunite / plaster pool that keeps the level pretty steady between 4 and 5 parts per million depending on the temperature. I have no algae problems, the water is crystal clear, and all chlorine is free. The problem is that the stains aren't even close to disappearing. My pH has been difficult to steady, but has been about 7.4 for the last week. The local pool specialist suggested that I use ascorbic acid to remove the stains, but that seems contrary to your advice. In fact, the pool specialist explained that I had to drop my Chlorine level in order for the ascorbic acid to be effective. Metal and mineral tests proved negative. Should I try the pH down in the sock trick or shock the pool with tablets to increase my chlorine level? Thanks.

Tony D, 2/23/2008

The evidence does point towards tannins, but the elevated free chlorine should have done the job. The only explanation would be poor circulation, such as if there was no main drain. Do you have a pool cleaner? Use it to improve the bottom circulation! Try
Stain Reversall Kit. sprinkling some trichlor granules on the pool stains and leave overnight. If this doesn't work, the problem is not tannins! A metal pool stain becomes the most likely cause of the problem. By all means try the pH reducer in a sock. If it doesn't work, try placing a few vitamin C tablets on the pool stain. If that works, then the use of METALTRAP Stain Remover should be the next step. You will have to lower the pH and zero out the chlorine level, in order to prevent the chlorine from destroying the stain remover. Once the pool stains are gone, add 2-3 doses of a quality, phosphate-free, metal treatment, such as Liquid METALTRAP. Allow to recirculate for 24 or more hours before storing the pH and chlorine levels.  BTW. There is a new Floating Pool Skimmer  that should be a great help, in controlling the problem with the leaves. It even functions, as a trichlor feeder.  Good luck and I hope that the information proves helpful.

Sincerely. Alan Schuster, 2/23/2008

Yellow Pool Staining After Salt Addition?

We have a 16 x 32 inground pool with a "SALT" system. We have had to add salt in November and December and on both occasions once the salt was dispensed it has left a discolored stain in the area where the salt was poured. The color is not black but a light brown. The company where we purchased the pool has been of minimal help. If you have the slightest bit of information please let us know as this pool is only 5 months old and I am trying to save the liner. Thanks.

Nameless, 12/31/2008

The pool staining that you are describing is not something normal or inevitable. The salt could have been of industrial quality and contained trace metals such as iron (yellow prussiate of soda added as an anti-caking agent), the pool water contained lowSaltron Reliant salt chlorine generator, for pools. levels of iron and, perhaps, the addition of the salt and the resultant high TDS caused the iron to precipitate or the salt was not distributed around the pool and/or was allowed to remain in prolonged contact, without the benefit of being stirred. Always use a food or water softener grade of salt. Never use rock salt! In either case, I would try adding a dose of pH decreaser to the pool and try to remove the pool stains (most likely iron) by applying acid. To do this take a white sock with 1/2 pound of pH decreaser powder and drop it onto the stained pool area. Leave it in place for a few minutes and slowly move around with the vacuum pool. Hopefully the acid will dissolve the pool stains. You can also try a similar technique using MetalTrap Stain Remover, which works better and more often. Periodic addition of a dose Liquid MetalTrap will help prevent staining and, in addition, help keep the salt chlorinator plates free of scale deposits. Liquid MetalTrap, unlike most metal treatments is phosphate-free and still performs, at a pH over 7.8. These high pH readings can be common, when a salt chlorine generator is in use. I hope that this information will prove helpful. Best wishes for the new year!

Sincerely. Alan Schuster, 12/31/2008

Where Did The Copper Come From?

I have a 14,000 plaster pool with a heater and was recently troubled with some discoloration. The dealer found 1.3 PPM of Copper. I never used a copper algaecide. So where did the copper come from? Please help. Thanks.

Larry P., Clearwater, FL, 2/4/2011

It would appear that you have dissolved some of the copper heater core. This is a result of low pH conditions over an extended
Liquid MetalTrap period and can be confirmed with a Copper Test. If your pH is too low, you must add something to the water before raising the pH. Add a double dose of a quality, phosphate-free, chelating agent, such as Liquid METALTRAP and recirculate for a day, before raising the pH or total alkalinity. This product should complex (chelate) the copper and avoid further problems.  If you are using TriChlor tablets there is a tendency for the pH to drop over time.  Test the pH several times weekly, at the very least. If you have an inline chlorinator, make sure that it is located after the heater and filter - NEVER BEFORE! I hope that I have been helpful.

Sincerely. Alan Schuster, 2/4/2011

Questionable Stain?

I have a 20 X 40 vinyl liner pool with a very large sand filtration unit but I use zeolite filtration media instead of sand. (Awesome stuff by the way). About mid season last year I installed an Ionizer (copper and silver type) on my pool to reduce the amount of chemical use. Near the end of the season I started developing a blackish stain in the creases of my pool (where the pool walls meet the bottom). I've done some research and believe it is a mineral stain from the copper or the silver used by the ionizer. I have discontinued the use of the ionizer and am simply using a chemical approach to sanitizing the pool and the stain growth has stopped. First, how do I get rid of the stain? Second, if I reintroduce the ionizer to the mix, how do I keep it from coming back?

Tim Y., 5/15/2004

It could be due to heavy metal pool stains or possibly algae. The trick is in narrowing the field, inasmuch as treatment is quite different. I suggest that you try something simple. Place a half pound of pH reducer powder in a white sock. Shut off the filter
Stain Reversall Kit. and drop the sock onto the pool stain. Position, as needed, with the vacuum pole. Leave in place for about 15 minutes. If there is improvement, the problem is positively due to a heavy metal: iron, copper or manganese. If this does not work, try the same thing using METALTRAP Stain Remover. If the pool stains are removed, add a double dose of a quality metal treatment, such as phosphate-free Liquid METALTRAP, now and add another dose monthly or whenever new water is added. If this fails, it is possible that the problem is black algae. Black algae is a resistant type and will require a regimen to remove. You will need to boost the Free Chlorine level to 10 PPM, add an initial dose of a polymer algaecide, add an initial dose of a quat algaecide and lower the pH to 7.0-7.2. Redirect the return flow to improve the water circulation in the affected area. Use a scrub brush on the stain, in order to expose the sub-surface to the chemicals. If you have to use a metal treatment, it will create a problem with the ionizer. The product will complex with the copper and reduce its algaecidal action. I suggest that you use a polymer algaecide, for at least a few months, should you resume use of the ionizer. I hope that this information proves helpful.

Sincerely. Alan Schuster, 5/15/2004

Tan and Brown Stains?

We have a 5000 gal fiberglass pool with heater, that slowly develops stains (brown or tan) on walls, pH 7.4, TA 120. These stains can easily be removed by a stain remover (concentrated ascorbic acid), together with a metal treatment. After treatment, pump is run for 12 hours then filter is backwashed and new DE added. We treat this problem when it becomes unsightly, approx every 6 weeks. Are you aware of any chemical/product that could be added on a continuing basis that would prevent this staining. It would be nice to have pool walls clean all the time. Could corrosion from heater be causing problem? Any other possible cause of problem? Thank you.

Tom K, 3/22/2004

The color, of the pool stains, is not consistent with copper, so I would rule out the heater. However, it is consistent with iron and so is the treatment that you have used. I suggest that you have the pool and source water tested for iron. Any level can be a problem. Iron can be present, even if the test results are negative, due to interference from other chemicals that might have been added or from the fact that it is on the walls and no longer present in the water. It sounds like iron, so I suggest that it be treated like iron. The recurrence could be due to not having added enough of the metal treatment or having added makeup water. Add a dose of the metal treatment now and add an additional dose monthly or whenever new water is added. Fiberglass has a negative electrical charge and can attract positively charged metallic ions, causing the development of a pool stain. The problem can be solved more effectively, with The METALTRAP Filter. This cartridge-like filter is used to recirculate the pool water and, as water passes through its special media, metals are permanently removed. If you use it to treat all new water and seasonally, thereafter, you should be able to better maintain the pool's appearance. Liquid MetalTrap is different from most metal treatments. It is phosphate-free and does not degrade to ortho-phosphate, over time and it is still effective at a pH of 7.8 or higher. The right metal treatment could have made a difference. Still nothing is better than removal and avoidance.  I hope that the information will prove useful. I hope that the information will prove useful.

Sincerely. Alan Schuster, 3/22/2004

Gray-Black Pool Staining?

Wonderful website! I am desperate. We have a 4 yr old gunite pool (16,000 Gal) we inherited when we bought the house 1 year ago. The pool has a cartridge filter and a heater. Although we don't use the pool in winter, we have it maintained just like in summer, so we could swim at any time, if we wanted to heat up the water (but we haven't this year). We have been using a pool company to clean and treat the water. We are on their regular stain treatment program. Never had any stain problems. Until this winter. First it started in the area near the drains in the middle of the pool, a big dark grayish/black area developed. Now within 2 months almost the whole pool is covered with the gray black stuff. I tried your pH minus in the sock trick - it worked. So I had the pool guys give me 10 more pounds of the stuff and started at 7 am this morning with the tube sock, trying to move it around the pool. The pH minus is dissolving very quickly, when I move it around on the pool brush with a tube sock. By now the whole pH of the pool is at or below 6.8 and all the pH minus is gone but probably around 2/3 of the pool is still stained. How should I proceed? Any ideas why all of the sudden the pool would start staining like this and the stain spreading over the months? We are in Houston, Texas and we have lots of pines around us and lots of wax myrtles. We do have an automatic cleaner and clean the skimmers and scrub the pool 2x a week. Water was filled up 4 inches 3x times last summer with no immediate effects on the staining. Thanks in advance for your help.

Marita S., Houston, TX, 2/17/2009

The problem could be caused by something in the water: iron, copper, manganese. Have the water tested. You may have
Stain Reversall Kit. subjected the heater to the corrosive effects of chlorine and low pH. If the acid made a difference, the problem is not algae or something due to the trees. At least not entirely. Tree stains and algae are best removed by shocking. Mineral stains will not come off with chlorine!  I suggest you place some vitamin C tablets on a pool stain and allow to dissolve.  If this works, allow the pool's chlorine level to bottom out. Drop the pH to about 6.8 and bypass the filter, if possible. Add 2 pounds of MetalTrap Stain Remover and recirculate the water. Brush frequently. Add a double dose of a phosphate-free Liquid MetalTrap and wait 24 hours before raising the pH or adding chlorine.  It sounds like the problem was too big for the sock treatment. Let me know how it turns out. Good luck!

Sincerely. Alan Schuster, 2/17/2009

I just stopped after 10 solid hours and 23 pounds of pH minus. I have not run the pump at all today, since there is no way to bypass heater and filters. My pH test kit only goes as low as 6.8, but it is much lighter than that colour, so I assume the pH is way down. After I emailed you, I used another 10 pounds of pH minus in the sock and kept spreading it around, but the stuff really only came off immediately underneath the sock this morning. I have also scrubbed my heart out, and it appears overall that probably 3/4 of the staining is gone or has lightened up, which leaves me with light shadings of gray in some areas. The pool guy only left me a pint of metal product. I had asked him for 3. So I went ahead and used the one pint I had, since I am worried about the dissolved stuff resettling. I was thinking of leaving the pH low until tomorrow PM and adding some more metal product in the morning and scrubbing again really well. I won't run the equipment until the pH is rebalanced. Do you think this will damage the plaster? It is already kind of worn off on all the corners by the pool cleaner and I had to patch 4 spots where the gunite was showing! We did have some green algae early this summer and it does appear that the very first black/gray stain (1ft diameter by the drain) appeared within a few weeks after the algae were gone. It seems like it disappeared after that so. Could the algae treatment the pool people used have caused this and, if yes, how could that have been avoided? And if it did, why would it keep spreading gray/black stuff for months after? And why is that chelated metal treatment they are using monthly for iron, copper, manganese etc not working? I know, lots of questions, but I am a pool novice and so tired and frustrated I am about ready to fill the thing with dirt and plant flowers! Thank you so much for your support and I have referred your web page to our pool guys!
Marita S., 2/18/2009

It is not algae. Algae wouldn't come off with acid. Yes, the acid will etch the surface a bit. Try and keep the chlorine level low, as
long as the pH is under 7.0, in order to help protect the heater. The overall acidic conditions should even out the appearance. If some spots remain, try locating a pool stain treating accessory and use it to siphon an acidic solution onto any remaining pool stains. I can't comment on why the products didn't work, as I have no information relative to their content. Possibly enough product was not added. It is possible that the algae treatment caused the start of the problem. Copper can stain masonry surfaces, especially in the presence of high levels of calcium hardness. Adding some Liquid Metal Trap, after the algae is gone, can help minimize the possibility of staining. Good luck.

Alan Schuster, 2/18/2009

Boy, Alan! Do we have a sparkling pool this morning! The pool guy just came by and couldn't believe the change either! Your help REALLY is appreciated, recommended your website to everyone I know has a pool. Thanks a million.

Marita S., 2/19/2009

I guess it doesn't get much better that this. Just make sure that you add a dose of a metal treatment monthly and prior to adding an makeup water. If you use algaecide, try a polymer based product. Glad that it all worked out.

Regards, Alan, 2/20/2009

Black Spots In Pool?

First of all the basics: 22,000 vinyl liner pool with skimmer and main drain, Chlorine treated Sand filtration. The pool gets black mud looking spots.  They can easily be brushed away, but return. I usually use a copper based algaecide. It has given some relief in the past but seems ineffective now. We keep our pool open year round but only swim in summer, we live in Atlanta. Have you got any ideas? Sincerely.

Mike G., Atlanta, GA, 3/10/2010

My best guess is that it is not black algae: this type of algae is very difficult to remove and will not simply brush
Liquid MetalTrap away. It is possible that copper can cause some black stains, especially if the pool water is high in calcium hardness, although this is unusual with the proper use of a chelated copper algaecide. I suggest that you discontinue use of the copper algaecide and start using another type, inasmuch as you stated that it seems not be effective. My choice would a polymer algaecide. It is more expensive, but worth the price. Try this on the pool stains. Put 1/2 pound of pH reducer in an old white sock, drop onto a spot. Leave in place for a few minutes and move around with a vacuum pole. If improvement is seen, this will confirm that it is a mineral problem and not algae. Repeat elsewhere as needed. To help prevent a recurrence of the problem, add a double dose of a quality, phosphate-free mineral treatment, such a Liquid MetalTrap. There are pool stain scrubbers available to help remove difficult spots. You might find more information in other areas of the archives. I hope that I have been helpful.

Sincerely. Alan Schuster, 3/10/2010

Gray Pool Stains?

I have a large in-ground pool/spa, 7 years old, kidney shaped, about 30,000 gallons. It has had a Copper Ionization + ozone system on it for about 5 years. Over the years, the pool service did not maintain the pH properly and the pool has developed gray stains. A drain and acid wash is recommended by my pool service but I am reluctant to proceed due to the expense and the impact it has on the pool surface finish. My pool technician, has suggested that he has been successful in treating stains like these with the addition of Muriatic acid to the water. I am willing to give this process a try as it appears cost effective and should not damage the finish. I would like to try the treatment on the spa first, and see if it is successful. If yes, than I would like to do it to the whole pool. What are the pros and cons to this approach? How much Muriatic acid needs to be added for success? My spa is 8 feet in diameter. How many gallons of acid for the 30,000 gallon pool? How long should I let this circulate? Are there different strengths of Muriatic acid? Which one should I use? What is the best way to restore the water chemistry after this operation? Thanks.

Minoo B., 12/1/2007

I frequently recommend that a pool or spa be subjected to an acid bath as a means of stain removal. Basically it dissolves the top surface and hopefully takes the pool stain with it. Lowering the pH will subject the metal parts to corrosion, including the heater, if chlorine or bromine are present. Therefore, treatment should be in terms of a short period of time - a day or less. You have to add enough acid to lower the pH below lower pH readings on the testers. A pH of about 5.5-6.0 should suffice. Use the brush to scrub the surface. Bypass the heater, if possible. Once the pool stains are removed, add a dose of a quality metal treatment, such as phosphate-free Liquid METALTRAP, in order to help avoid a recurrence. Restore the pH and TA. Because the addition of the metal treatment could interfere with the copper being introduced by the ionization unit, I would recommend using a polymer algaecide for a month or two, while the copper ion content is re-established. I hope that this information proves helpful.

Sincerely. Alan Schuster, 12/1/2007

I used your recommendation and the pool/spa surfaces are now to almost all-new condition. Thanks. There is one problem I am having that I have not been able to solve. The pH continues to remain high (around 7.8 to 8), the TA is fine, and repeated attempts by my pool service and me to lower the pH by adding acid have not been successful. My pool service thinks that the pool/spa surface areas are still leaching chemicals and are planning on adding some chemicals that will help. Any suggestions based on your experience? Sincerely.

Minoo B., 12/4/2007

It is possible that the walls are leaching into the water and causing the pH to rise. To help prevent this, check the calcium hardness level. If the level is below 200 PPM, raise it to that level. If the calcium hardness is above 200 PPM, the answer to the problem may lie elsewhere. I hope that I have been helpful.

Sincerely. Alan Schuster, 12/4/2007

Brown Pool Liner Stains?

I have a 18x36 inground pool. Rectangle with radius corners. The pool is 6 years old. We have brown-colored stain on the pool liner. Is there any way to remove this? What caused it? We have never had this type of pool staining previously. Thanks.

Becky S., 5/7/2008

It is difficult for me to know, with any certainty, what has caused the vinyl pool liner to become discolored and stained. The problem could be pool stains from leaves and debris or a stain from algae. If the pool was just opened, these possibilities are
Stain Reversall Kit. likely. The colored pool stains could, also, be caused by the presence of heavy metals such as iron or copper. Having the water tested for iron and copper could shed some light on these possibilities. If you think the problem is leaves or algae, it, should be removed by shocking the pool water. Raise the Free Chlorine level to 5-10 PPM. This should show improvement within a day or so. If the problem is minerals, you can try this as a means of confirmation. Put 1/2 pound of pH reducer granules in a white sock. Shut off the filter. Drop the sock onto a stained pool area and leave in place for 15 minutes. Use the vacuum pool to move it around. after 15 minutes. If improvement is seen, the problem is definitely minerals. To treat the entire pool, it will be necessary for the pH to be dropped to approximately 6.0. This will dissolve the pool stains. Use the brush to speed things up. Afterwards, add 2-3 doses of a quality mineral treatment, such as phosphate-free Liquid METALTRAP, in order to complex the minerals and help prevent a recurrence. If you are on well water, using the METALTRAP Filter, to treat all new water, helps keep new additions of iron and other metals out and minimizes the possibility of pool staining. You could, also, use The METALTRAP Filter to recirculate the pool water and lower the heavy metal content. I hope that I have been helpful. Good luck.

Sincerely. Alan Schuster, 5/7/2008

Stained Gunite Pool?

Dear Alan, I tried your sock trick with pH decreaser and it worked on the pool stain. My problem is the pool store said that if I use to much muriatic acid to lower my pH to 5 it would destroy the surface of my gunite pool. They are in the business to sell chemicals. Please advise as soon as possible. Thanks.

Bill L. from Florida, 11/11/2006

You'll need to fill in some of the blanks. The sock trick worked? Did it work in a spot or everywhere? Is the stain local or overall? You may have to just lower the pH into the mild acidic ranges and that should no permanent damage. It would be like an acid wash. I'll get back to you after your reply.

Sincerely, Alan Schuster, 11/11/2006

I tried the pH decreaser on the steps of my pool and also in the deep end I believe the stains to be iron since I use well water to fill the pool. I used a vitamin C tablet and it also removed the staining, but not as quickly. How low can I lower my pH without adverse effects? Also can I use muriatic acid since it is much less expensive then dry acid. I hope you have enough info. Sincerely.

Bill L., FL, 11/12/2006

You must have the pool and well water tested for iron. You will need to add one dose of a quality iron treatment, for each one PPM or fraction - ASAP! In the future add more after each addition of new water. This will not remove the pool stains, but should help prevent more. From what you are saying, it is apparent that acid will remove the pool stains.  That being the case, I suggest that you allow the chlorine level to drop to just a few tenths of a PPM. Lower the pH to 6.0-6.5, by the addition of muriatic acid.
Dual-Cartridge Filter System. In this application, there is no benefit in applying dry acid. It will only cost more and make zero difference in the corrosion. Only the pH matters. Once the pH is lowered, use the brush to scrub the pool stains. Keep the filter operating and, if possible, by pass.  Periodically check the pH to see if more acid is required. The acid will etch the upper surface of the walls and by doing so will help remove the pool stains. The same etching would result from acid washing the pool. The lower the pH - the faster the removal process. Once the pool stains are removed, add another dose of iron treatment, prior to raising the pH. MetalTrap Pool Stain Remover will speed things up, if you add it just prior to adding the acid and while the chlorine level is very low. This chemical will discharge all of the chlorine in the pool and will make a shock treatment necessary to restore a chlorine level, after the pH has been optimized. However, before shocking allow at least 24 hours for the iron treatment to work. Inasmuch you are on well water, using the METALTRAP Filter, to treat all new water, helps keep new additions of iron and other metals out and minimizes the possibility of staining. You could, also, use The METALTRAP Filter to recirculate the pool water and lower the heavy metal content, already present in the pool water. If sediments are also a problem, the MetalTrap Dual-Cartridge Filter would be a better choice. It is a MetalTrap Filter, with a 5-micron sediment/contamination filter. The filter cartridges are replaceable and installation and use is simple. I hope that this information will prove helpful.

Sincerely. Alan Schuster, 11/12/2006

Dear Alan, thanks for the advice. I did as you suggested and it worked out great. The walls of the pool look great. I will use an iron treatment, in the future, whenever I put water in the pool. Thanks again. Great site. Good advice. Sincerely.

Bill L., FL, 11/15/2006

Brown Pool Walls And Bottom?

Alan, Your pH-reducer-in-a-sock trick did WONDERS for our 7 yr old vinyl lined pool BOTTOM. Within literally minutes, the brownish stains on the bottom disappeared. Problem:  The stains are still on the sides of the pool, however, and we cannot seem to get them off.  Our attempted solution. We tried rubbing the sock on the sides, but were unable to stand there long enough for the trick to work.   We treated the whole pool, as you suggested, but the pool stains persist, only on the sides. Any other suggestions? Sincerely.

Stephanie M., Edmond, Oklahoma, 5/17/2004

Stains on a vinyl liner will rarely ever respond just to the addition of Liquid MetalTrap. Acidic water conditions are usually required. Such products can help avoid further pool staining, but may not act upon a current pool stain.  The fact that the sock worked shows that the problem has a solution. It is case of lowering the pH of the entire pool to below 7.0.  From your description, it appears that iron pool stains are the problem and this treatment should work. However, it may work faster and better, if you allow the chlorine level to bottom out and add some MetalTrap Stain Remover, after the pH has been lowered to about 6.8. Once the pool stains are gone, add another dose of the metal treatment. Thereafter, add a monthly dose or whenever new water is added. Good luck and enjoy the summer.

Sincerely. Alan Schuster, 5/17/2004

Alan, I LOVE your site, and have told all my pool owner friends about it! As a follow up to my earlier question, we FINALLY got all the stains off of our pool. In fact, it has never looked better. We followed your advice about the pH reducer in a sock, and that got rid of all the bottom stains. Then the local pool supply store told us to rub a lemon/orange/vitamin C tab on the stains to see if that got them off. They started coming off instantly, so we went ahead and bought their stain remover product that was sheer concentrated ascorbic acid. (Confirming what you said about acidic conditions being necessary). We did not follow the instructions and broadcast the product in the water; rather we put it in a sock again and rubbed it along the sides. Thought the vitamin C thing might help someone else. Thanks a million!

Stephanie M., 5/18/2004

Stains From H--l?

Alan: I have a gunite pool built in 1959. The previous owner's neglect has created brownish/black colored pool stains from leaves and there is also a very light greenish blue colored pool stain. I drained the pool thinking a muriatic acid wash would take care of this. I was so wrong. Using a 4:1, acid to water, it did not even scratch this stuff. I need to get water back in the pool because of the massive amounts of rain we've had. Please give me advice on chemicals, treatments, etc. I can't really afford to refinish and I was told that paint, because of the cratered surface, would peel quickly.

No Name, 5/13/2011

Ultra Poly One Coat is a Hybrid-Epoxy Coating for refinishing plastered or fiberglass pool, spas or fountains.
The brownish pool stains are probably tannins from the leaves. Fill the pool up and a double dose of a quality mi
neral treatment, such as phosphate-free Liquid METALTRAP, just in case the pool stains are more than tannins. Add shock and boost the Free Chlorine level to 5-10 PPM. Tannins will be destroyed by the chlorine. Keep the Free Chlorine level elevated until the dark stains are removed. Keep the filter operating and use the brush. After these pool stains are removed, you will in a better position to access the appearance of the pool. The greenish pool stains could be algae and/or copper. If it is algae, the chlorine will take care of it. I am no expert on painting the pool, but at the very least you will have to thoroughly clean the walls before painting them and this is a good start on that road. One type of paint is especially easy to prepare for: Ultra Poly One Coat. Let me know how the first part turns out and we'll try to deal with the remaining problem. Good luck and I hope that the information proves to be helpful.

Sincerely. Alan Schuster, 5/13/2011

Rusty Stains On Fiberglass Pool Bottom?

Dear Alan, I recently had a fiberglass pool put in.(4 months ago) A short time later I saw my first couple of stains. One is a 2 inch streak 1/4 inch wide, my pool man who only ads the chemistry thought it might have been from a nail. I had a house built right next to the pool. The others seem more round and streaks like a meteor they are fairly small but I'd like to get rid of them without destroying the gel coat on the fiberglass. Any suggestions are welcome. The pool manufacturer thinks the pool guy might be adding the chemicals that settles on the bottom and causes these rust looking pool stains. Thank You.

Kris, 4/27/2007

None of the chemicals that the "pool guy" is adding should be capable of creating a pool stain problem. There are two likely causes of a discolored or stained pool. The source water added to the pool contains iron or other heavy metals. You can confirm this by having the pool water tested: most pool professionals offer complimentary water analysis. The other equally likely possibility is a foreign object. Start by adding a dose of a Liquid MetalTrap This will complex with iron and help prevent further staining. To remove the pool stains, a good option would be to use a stain-remover accessory. This inexpensive device is available at many pool stores and will allow you to siphon a solution onto the stains. To make a suitable solution: to a 1/2 gallon of water, in a plastic container, add 1 quart of a Liquid METALTRAP and 1 quart of muriatic acid. Make sure that you wear rubber gloves and eye protection! Because your pool is still under warranty, I would discuss this treatment with the builder, so as not to risk voiding the warranty. Use the stain-remover accessory to siphon the liquid onto the stains. Afterwards, adjust the pH, as necessary. Fiberglass pools have a negative electrical charge and can attract positively charged metallic ions, possibly causing the development of a pool stain. Using the METALTRAP Filter, to treat all new water, helps keep new additions of iron and other metals out and minimizes the possibility of pool staining. You could, also, use the METALTRAP Filter to recirculate the pool water and lower the heavy metal content, already present in the pool water.  The periodic addition of Liquid METALTRAP should help maintain this condition and help keep pool stain free. I hope that I have been of assistance. Good luck.

Sincerely. Alan Schuster, 4/27/2007

Stains From The Reverse Side Of Liner?

My pool has some grayish pool stains in the hopper. I have tried everything: shocking, rubbing with a chlorine tablet and ascorbic acid and nothing has helped. It seems to start in the spring and spread and darken as time passes. The dealer says that it a fungus growing on the reverse side of the liner and I'll have to live with it. Is there any suggestion that might help? Thank you.

Mike T., 6/11/2009

Information on this topic is very sketchy. The only person I had a conversion with, in depth, does not want to have his name made public. He is not in the liner business and, therefore, does not want to handle the inquiries. It is not a common problem. But if you have the problem that is no consolation. 

Some types of bacteria and/or fungi, found in the soil, can actually appear to penetrate a vinyl liner and cause pool stains to appear on the liner. Usually they will start off as spots or cloud-like formations on the liner. Chemicals used to elimination algae and other microorganisms have little or no effect, on these types of pool stains, since it doesn't get to the source of the microorganisms in the soil.

If a pool is thought to have a problem with microorganisms, mold or fungus staining reverse-side of the liner, the ground underneath the liner should be replaced with fresh sand, vermiculite or pool base. Afterwards, treat with a solution of one-part liquid pool chlorine and three-parts tap water. Apply with a garden sprayer several times. Wait a few hours, before prior dropping the liner into place. If it is not a new liner, please bear in mind that the liner could shrink and become useless, if allowed to dry out completely. An alternative to the chlorine/water spray would be use a non-solvent based herbicide on fresh sand, vermiculite or pool base.

If the liner has been recently replaced, one method which has been discovered that may provide a solution.  The application of Ferrous Sulfate (FeSO
4), to the perimeter around the outside of the pool can change the pH and the soil chemistry. This chemical is a reducing agent and exhibits acidic properties. This technique seems be effective in retarding and/or killing the troublesome bacteria, mold or fungus. This stems from a method used to protect the vinyl liners used under some landfills. This may not a guaranteed cure, but has been met with some success.  It can be tried without having to drain the pool and replace the liner. For an typical inground pool, you might require twelve to fifteen pounds of this chemical. Sprinkle it on the ground, around the outside pool perimeter, near the pool patio or deck, on as much of the pool perimeter, as possible. Afterwards, turn a lawn sprinkler on the area, for two or three days: long enough to get the ground around the pool thoroughly saturated with water. The intent is to get the ferrous sulfate to soak deep into the ground. Hopefully, it will change the pH and soil chemistry enough and kill off or retard the growth of these troublesome microorganisms. Results may not be seen for a few weeks, depending upon the nature of the soil's chemistry and drainage properties. Direct application of chemicals can damage some plants or grasses, so abundant watering and drainage is important. Ferrous sulfate is used with plants such as: Rhododendrons, Azaleas, Blueberries, Mountain Laurel, Holly and Blue Hydrangea, that thrive best in acidic soil. Do not allow this chemical to get into the pool, as it will cause water discoloration and staining of underwater surfaces. An alternative to the surface distribution would be the digging of a series small holes around the pool perimeter and burying some of the ferrous sulfate, in each one. Follow with a thorough watering down of the area, for the next few days.

Sincerely. Alan Schuster, 6/11/2009

Grout Stains?

Our pool has a salt chlorine generator and the grout has become stained.  Is there a specific kind of grout that should have been used with our tiled salt water pool?  We feel that the problem may rest in the minerals and metal leaching up from the gunite. Thanks.

Janet, 11/16/2011

Model SR salt chlorine generator, for all types of pools.
This is not a salt chlorine generator issue. There are different types of grout and some are much more resis
tant to staining. Products with silicone or epoxy should be less apt to stain, than strictly masonry products. Try using METALTRAP Stain Remover and a scrub brush, after lowering the water level. Follow with phosphate-free, Liquid METALTRAP, which is a true chelating agent, to prevent a recurrence. The minerals, in the plaster, should not have cause the problem. It could be the nature of the source water of the use of salt that contains Yellow Prussiate of Soda, which contains iron. I hope that this will help solve the problem.

Sincerely. Alan Schuster, 11/17/2011

Ascorbic Acid Worked Immediately?

I have the light brown pool stains on a vinyl pool. An ascorbic acid product worked the best. Immediately the stains disappeared. The problem is I can't find any locally. Can you tell me of any other similar products that national pool places would carry? Thanks.

Maria, 5/20/2009

Ascorbic acid be very effective in removing iron stains, especially if you can get the chemical to the strain. It is functioning as an acidic reducing agent. MetalTrap Stain Remover is available, in the website store. More people prefer its use, to that of the more common oxalic acid products, because oxalic acid is a toxic chemical. Good luck.

Sincerely. Alan Schuster, 5/20/2009

The Tough Last 10%?

Without a doubt the very best site I have seen yet on the problem of pool stains. We opened our 3 year old vinyl 20-40 pool and had a ton of dead leaves and junk that ended up on the bottom. Pulled out as much as possible and then vacuumed up all the brown "dirt" junk on the bottom. 90% came right up but some did not, it is as though it is "painted" on to the bottom. The interesting thing is that it follows the pattern of the vacuum attachment, that is, it looks as though the brownish color was "rubbed into" the vinyl. The pool water is incredibly clear. The stuff will not vacuum up easily. Using a rubber gadget, sort of like a large eraser, allows me to rub some of it off but this will take forever. Does this sound like a metal stain (iron). I did have some brown chalky dirt on the plastic returns in the pool which I understand is a sign of metals but the stains have definitely been "rubbed into" the vinyl which I would assume is more like a vegetable type or tannin stain. Anyway, I am open to suggestions. Thanks.

Ray S., 6/19/2007

Obviously tannins would have been my first choice. The circumstances all point to tannins as the cause. The statement that the water is clear leads me to believe that the chlorine reading is acceptable. The fact that you can rub it off eliminates the
Liquid MetalTrap possibility of it being a fungus on the reserve side of the liner. That does leave open the possibility of iron and or other metals. Try this! Put 1/2 pound of pH reducer powder in a white sock, shut off the filter and drop onto a stained pool area. Leave in place for 15-30 minutes. Move with a vacuum pole and, if improvement is seen, the problem is definitely minerals. You might be able to treat the problem by repeating this procedure. If the problem is mineral you will need to add a double dose of phosphate-free Liquid MetalTrap, in order to help avoid a recurrence. You can use a stain removal accessory to scrub the remaining stubborn spots. If the sock trick, does not work, I am inclined to believe that it is a plant-derived pool stain or early stages of a resistant algae. I would treat this on the basis of being black algae and add a polymer based algae and boost the Free Chlorine to 10 PPM. I hope that this leads to success. Refer to the archives on Black algae for additional information. Thanks for the encouragement. Enjoy the summer.

Sincerely. Alan Schuster, 6/20/2007

Algae Stains Or Mineral Stains?

Hello Alan. You have a great web site. It has been so helpful. I do have a pool stain problem with my in ground 16 X 38 pool. I have some stains that appeared in the bottom of my pool. It is a vinyl liner. All of the stains are at the bottom where the side walls meet the bottom and at the corners of the slopes down to the deep end. It is tan and beige in color. I tried scrubbing the areas and no success. I was told to try putting a 3" tablet in a sock and scrub the area and see if it lightens up. That did not work either. I was told that it could be black algae and I also was told that it could be a metal pool stain. The testing of the water showed no metals in the water. What would be my next step? Any help would be appreciated. Thank You.

Ralph, 6/13/2008

I would advise you not to try that thing with the tablet in the sock. It might work, but it might bleach the liner. You can remove a stain, but you can't undo the bleaching out of the liner color. The areas that you are describing are some of the favorite hangouts of algae. It is also possible that mineral particles accumulated in these areas and led to the discolora
tion. From the color it is not clear cut, as to the possibilities. TColorQ all-digital water analyzers, for pools and spas.he fact that the water does not show metals is not conclusive. The metals may have precipitated out of the water or may not have been tested for. I suggest that you start by trying my sock trick. Put 1/2 pound of pH reducer in a white sock and drop onto a stained area. Position with a vacuum pole, if necessary. Leave in place for 1/2 hour. If the pool stains are removed, it is proof that the problem is mineral. If this did not work, try it with a pool stain remover, such a MetalTrap Stain Remover, instead of the pH reducer. If the discolorations and pool stains are not removed, it is possible to probable that it is a resistant type of algae. If this is the case, I suggest that you treat it on the basis of black algae. You'll find more information in the archives on that topic. You might want to take a more active role, in the water testing. The ColorQ all-digital water analyzers have helped many a pool owner get a handle on a problem. There is a model, for every pool need. No color-matching and it eliminates the guesswork. I hope that this information will point you in the right direction. Good luck and let me know how it turns out.

Sincerely. Alan Schuster, 6/13/2008

Pool Stains Caused By Leaves?

Do you know of a stain remover that will work on leaf pool stains? We had a problem when closing the pool, and the water was not clear, and leaves set all winter. The pool now has a green tint, and looks like algae, but tests good. Thanks.

Trish, 4/20/2006

You don't need a pool stain remover. Most likely the stains are tannins from the leaves and would have resulted in brownish
Remote Controlled Pool Surface Skimmer. colored pool stains. The green color of the pool water is. most likely, due to algae. Shock the pool and keep the Free Chlorine Test reading at approximately 5 PPM, until the water clears up. The elevated chlorine level will decompose the tannins and the algae at the same time. Use a brush on the stained pool surfaces to speed things along. Keep the filter operating continuously. Retest the Free Chlorine periodically and add more shock as might be required. After the water clears and the stains are gone, resume normal filtration and chlorination. A Remote-Controlled pool surface skimmer can remove the leaves, before they have a chance to sink to the pool floor. Joy-Stick operated, the kids will want to clean the pool.  I hope that I have been helpful.

Sincerely. Alan Schuster, 4/20/2006

Cause Of Exposed Aggregate Stains?

I have a 1-year old pool running on a salt chlorinator.  The water balance has been maintained pretty much dead center. However, on two occasions the salt system blew a fuse and stopped generating chlorine for a week.  In the shaded area of the pool I developed algae after the second blown fuse. Iíve been told that the discolored areas now on the exposed aggregate surface are algae that have impregnated the surface. Iíve tried recommended doses of stain removers for yellow, non-metallic type pool stains with some success. The stains have definitely been lightened, but theyíre still there. My questions: Is my information correct? Have algae impregnated themselves into the aggregate? Can I double or triple the dosage of products recommended for removing that sort of pool stain? Is there a product on the market that will work well on this sort of pool stain? Lastly, I know algae can grow quickly, but, Iím skeptical that this pool stain was caused within a 1 week period, simply because of the salt system shut down. Iíve had pools in the past with tons more algae and never any pool staining.  Could this be because the surface was so new when the outbreak occurred?  It happened within 3 months of being filled with water. Thanks for your help.

Mark M., 2/3/2010

I can point you in the right direction, but the exact cause is for you to discover. Algae can grow very quickly, especially in warmer water that is lacking chlorine. Algae can stain and get imbedded in the rough surface. Given that the salt chlorinator was inoperable for a week, this seems the most likely cause of the problem. Metals can stain, especially in a pool that is relatively new. I doubt that there was anything inherently wrong with the finish. So which is it? Adding all the metal treatments will do nothing, if the problem is algae-related. A high dose - 10 PPM - of free chlorine would be much better in this case. Try and redirect the flow to send more water towards the effected areas. If the stain is metals-related, shocking the pool will accomplish nothing. You might need to lower the pH and add some MetalTrap Pool Stain Remover, after the chlorine level has been dropped closer to zero. Give the sock trick a try or place a few vitamin C tablets on a pool stain. If this works, the problem is definitely metals. If it fails to work, it is most likely algae. Good luck and I hope that the information proves helpful. Please let me know how it turns out.

Sincerely. Alan Schuster, 2/3/2010

A Wintertime Mistake?

Greetings Alan, I came across your website and I am unclear if some of the questions pertain to me. We covered our pool last winter with the cover and tied most of it off. During some windy days my husband put some weights round the pool to hold the liner down, unfortunately one fell in and left quite a large size rust mark. We live in the Toronto Canada area and are looking for ways to scrub away the rust stain. Some removed with a pool brush however there is a significant amount left. Could you please assist! Thank You. First time pool owners.

Dale and Jacquie H., Toronto, Canada, 6/10/2009

I'll assume that the pool is vinyl lined. Try this! Put 1/2 pound of pH reducer powder in white sock and drop onto a stain - use the vacuum pole to position the sock. Leave in place for 15 minutes. If improvement is seen, repeat elsewhere, as needed. If it doesn't work, you might try using MetalTrap Stain Remover, instead of the pH reducer. You can also use a stain-remover accessory to remove the pool stain, by siphoning an acidic cocktail onto the stains. This device is available at many pool stores. In the future, use water bags to hold the winter cover in place. Good luck and I hope that I have been helpful.

Sincerely. Alan Schuster, 6/10/2009

Stained By Neglect?

Hello, I appreciate your advice. I am a new home owner with a new pool, which is said to have been re-plastered last year w/ blue plaster. I expected the pool to be in good shape when we moved in. However, it appears the previous owner had stopped maintaining the pool for at least two months. By the way, this is in El Paso. We get high winds this time of year with lots of dust, the pool has no cover. I immediately vacuumed the pool and tested the water. It was low on chlorine. I expected the floor of the pool to get clean completely. However, I was surprised to find that not all of the dirt came up.  Throughout the floor of the pool there is a faint grayish layer of what appears to be dirt. However, there appears to be tracks running back and forth along the whole bottom of the pool, that I would assume were made by the wheels of a vacuum. These tracks run back and forth in predominantly one direction, and the pool surface looks clean where the tracks are. I don't know how to describe it further, other than the bottom just looks dirty with all these "clean" tracks running through it. Can you help with any advice? Your recommendations are greatly appreciated.

Frank H., El Paso Texas, 4/25/2007

There are several possibilities. The neglect could have resulted in algae and debris accumulating and causing a discolored, stained
One of the ColorQ all-digital, pool and spa water analyzers. pool. If this is the case, a shock treatment should remove the discoloration. Boost the Free Chlorine level to 5-10 PPM and keep it there for a few days. The problem could be minerals. A water analysis should shed some light on this possibility. Have the water tested for iron and copper. You might try this. Put 1/2 pound of pH reducer powder in a white sock and drop onto a stained pool area. Shut off the filter and allow to remain in place for 15 minutes. If improvement is seen, the problem is minerals. If no improvement is seen, algae and debris staining are more likely. Your local pool store should have a gadget that can attach a 3" inch tablet to the end of a vacuum pole. Use this to rub a chlorine tablet on a stained pool area. If improvement is seen, the shocking of the pool should do the trick. The right kind of water analysis information can solve many problems. The all-digital ColorQ testers eliminate the color-matching and guesswork. If it helps you avoid problem, that is time and money saved. Browse through the archives for more on this topic. Good luck and I hope that I have been helpful.

Sincerely. Alan Schuster, 4/25/2007 

You've given me some good ideas on how to proceed. Sincere thanks for your response.

Frank H., 4/28/2007

Mystery Pool Stains?

The pool store we used closed this past year. Right after that, we installed a chlorine generator on our 18 x 48 inground vinyl lining pool. We always had clean sparkling water with chlorine, and for the first couple of months, the water was fine with the generator. Now the sides of the pool have become stained. This LOOKS like an algae but it is a pool stain - even the stainless steel ladders have stains around the water level. This baffles me! The generator registers 2800 to 3200 so I'm sure we're putting enough salt in the water. Is this a normal occurrence with these generators? We've always had the prettiest pool in our neighborhood and now it looks like it's dirty. I know the water is clean though. I worry that, should we put in a new liner, will it become discolored too? If you can help me, I surely would appreciate it!

Colleen, Central Georgia, USA, 5/12/2009

The pool stains are probably due to iron, copper and other trace minerals and are rarely removed by simply adding a metal treatment. The pool stains are probably completely unrelated to the salt chlorine generator. Try this. Place 1/2 pound of pH minus
Stain Reversall Kit. in a white sock and drop onto a pool stain. Leave in place for 15 minutes. Move around with a pole. If this works, you should be able to get rid of the pool stains by lowering the pH of the pool to about 6.0. If you have a heater, by pass it or allow the chlorine readings to fall to zero. In it does not work, place a few vitamin C (ascorbic acid) tablets on a pool stain, shut off the filter and leave in place for 15 minutes. If this worked, it is likely that treating with MetalTrap Pool Stain Remover will work. Put 1/2 pound in a white sock and drop onto a pool stain. Slowly move around with a vacuum pole. Repeat elsewhere, as necessary. Some pool dealers carry these products. Have the pool and source water tested for iron and copper. ADD A DOSE OF A PHOSPHATE-FREE LIQUID METALTRAP FOR EVERY 0.5 PPM OF IRON OR COPPER. At the very least add two doses. If the stained pool area is too broad to be treated with the "sock", you may have to lower the pH of the pool to 6.0, discharge all of the chlorine and add a few pounds of MetalTrap Stain Remover. If there are questions regarding this get back to me with the test results and the results of the "sock" test. Thereafter add a dose of metal treatment monthly or prior to adding new water, in order to avoid minimize the possibility of a recurrence. Good luck and I hope that I have been helpful.

Sincerely. Alan Schuster, 5/12/2009

Alan, I just found your letter - I'd saved it. Just thought I'd let you know, I just took a sample of the water to a pool store and bought what they recommended and did what they said! You were so kind to try and help me out! I just need a "pool man" to come every week. Actually, life with the chlorine generator is simple. I just know now that I still have to test my water. Have a happy and safe Memorial Day.

Colleen, 5/29/2009

Rust Stains From Steel Wool?
We recently did some work in our back yard using steel wool. Particles of the steel wool ended up in our inground pool. Small rusty pool stains, from the steel wool are appearing. Is there something I can use on these small pool stains to remove the rust without emptying the entire pool? Thanks.

Mike C. Scottsdale, AZ, 10/2/2011

NEVER USE STEEL WOOL AROUND A POOL!!! First start by adding a dose of phosphate-free Liquid MetalTrap. This will chelate (complex) with iron and help prevent further pool staining. To remove the pool stains try this: put a pound of pH decreaser in a white sock and drop onto a stained area. Leave in place for a few minutes and slowly move to other areas with the vacuum pole. It should dissolve the pool stains. A better option would be to use a stain-remover accessory. This gadget (available at many pool stores) will allow you to siphon a solution onto the stains. To make a suitable solution: to a 1/2 gallon of water, in a plastic container, add 1 quart of Liquid MetalTrap and 1 quart of muriatic acid. Make sure that you wear rubber gloves and eye protection!  Use the device to siphon the liquid onto the pool stains. Afterwards, adjust the pH, as necessary. Another type of accessory allows you to scrub the stains away and might be a simple and effective way to deal with the problem. If the pH Decreaser did not work, try the same thing using MetalTrap Stain Remover. I hope that this information proves helpful.

Sincerely. Alan Schuster, 10/2/2011

Product Of Neglect?

Great website, I have found it very useful. I have a problem with some staining on the plaster of my in ground gunite pool. I read through the replies to other's problems and didn't see this addressed. The pool is about 7 years old and was not taken care of by the previous owners. We inherited it 2 years ago and it was green and dirty with the staining I describe below. I have heard from neighbors that it was partially filled and left unattended for some time. I have had a pool service for the last 2 years. I took the water in to a local store today and it had: Free Chlorine=5.0, Total Chlorine=5.0, pH=8.0, TA=260, CYA=90, Calcium Hardness=1075 (very high!), TDS=2500+ (very high!, off the scale they had). They pointed out that the TDS was extremely high and that the pool should be drained and refilled. Also the CH was very high. I am in San Diego, CA, where we have hard water, but the store said that the CH from the tap is about 200, so tap water should be fine. Here is the problem. I have a medium to dark blue plaster finish and there is some staining or discoloration on the uppermost step (foot step) and the bottom at the deepest part of the pool (about 6 feet deep) around the drain, maybe a 5 foot diameter area. The discoloration looks like the dark blue finish has lighten up to almost light yellow to white, it is very uneven and erratic in color, almost like something has eaten into it, although the surface is not unusually rough. The discoloration at the top step (there's none or very little on the lower steps) appears to be a result of the floating chlorine tablet holder floating over or sitting above the step, almost like the chlorine leaching out of the floater and bleaching out the color in the plaster. The staining in the deeper part of the pool looks similar. My pool service guy believes that the color in the plaster has been bleached out. His explanation for the staining on the bottom of the pool is that someone previously placed chlorine tablets in the skimmer basket, which created a high concentration of chlorine when the pump was off, and this concentrated liquid traveled down the pipe (since the bottom suction pipe comes up just below the skimmer basket) to the bottom drain and had a similar bleaching effect as the step had. There are some spot stains around the pool in various spots, maybe 2 inch diameter, and he felt that small pieces of chlorine tablets may have fallen out of the floating chlorine tablet dispenser and stained the bottom. He felt that the pool would have to be replastered to fix the stains. Since my pool chemistry is pretty out of whack, I am feeling less confident in the answers I am getting from him. What are your thoughts? Would acid washing work? Can the plaster lose its pigment/color from chlorine? Any guidance would be very helpful. Thanks.

Ron L. San Diego, CA, 2/11/2011

Obviously, the pool was badly neglected. That may be the only certain fact! The skimmers connect to a valve near the filter and not directly to the main drain. There's no likelihood that backflow caused these problems. It is not likely that trichlor tablets were, necessarily, used for long periods of time - otherwise the cyanuric acid level would have been much higher. If the water was
Ulta Poly One Coat hybrid-epoxy coating, for pools and spas. partially drained to lower the CYA reading, why are the calcium and TDS so high? To me it sounds like your pool has experienced severe etching, possibly to deal with scale deposits. The fading colors may have been caused by chemical action. The pool is 7 years old and a refinishing is, at best, a near term expectation. You could drain the water to lower the calcium hardness, which is really too high for proper pool water management. You could try to acid wash the pool, but from your descriptions, it does not sound like it will do an effective restoration job. Why spend money on acid washing, chemicals and replacement water, only to decide later that the only and best hope is a resurfacing of the pool? I would opt for the pool resurfacing, if it is a budgetary option.  Painting is a viable option. It will cost less and will make the water chemistry easier to maintain.  Ultra Poly One Coat has a 15-year warranty. Read the first letter on this page: Pool Coatings and Paint. After the pool is back to prime condition, I would suggest that you use an alternative means of sanitizing, in order to better preserve your investment and have fewer water chemistry problems to deal with. ozone generators, salt chlorine generators or Ultraviolet Sterilizers are some of the methods that will replace the chlorine floater or the tablets in the skimmer (always a bad idea). I hope that I have put you on the right path.

Sincerely. Alan Schuster, 2/12/2011

The Whole Pool Stain?

I would like to refer back to this question from Ralph, 6/13/2008. My uncle had this stain and tried your solution, the pH reducer, and it removed the pool stain. But I cannot find a solution to removing it from the whole pool. Please help!

Lisa, 7/10/2009

If the sock trick worked, it is likely that lowering the pH of the entire pool will remove all of the staining from
Stain Reversal Kit.the pool walls, bottom and steps. Add muriatic acid to drop the pH to approximately 6.5. You'll probably have to guess with the test kit. Make sure that it will well below 6.8. If possible bypass the filter and heater and keep the water moving. Use the brush on the walls. Retest the pH periodically to make sure that it is remaining low. If possible, allow the chlorine level to remain low. Once the pool stains are removed, add several doses of a quality, phosphate-free mineral treatment, such as Liquid METALTRAP. This will help complex the offending mineral and help avoid a recurrence of the problem. Allow at least a day, for the mineral treatment to be distributed and to react with the redissolved minerals.  Slowly raise the pH back to normal ranges. In the future, add a dose of Liquid METALTRAP before each addition of new water or use a METALTRAP Filter. I hope that the information proves helpful. Good luck and enjoy the summer.

Sincerely. Alan Schuster, 7/10/2009

Staining Down Under?

Hi, I'm from NSW Australia and have come across your site. Hope you can help me as no one over here can. I have a fiberglass, salt pool that I am very fanatical about keeping clean. I keep getting a brown stain, that with the assistance of my local pool shop I get rid of only for it to return a couple of weeks later. My cartridge has been stained red from this stain. It starts out on the bottom of the pool only up the middle about 1 & 1/2 meters wide and then goes onto the sides. I keep my pH at about 7.2, alkalinity is usually about 60 as I hate to keep adding acid to keep the pH low as per the pool shops instructions to keep the stain at bay and chlorine levels are always correct. I test my water daily. Over the past 2 months the salt cell has been clogging up on a weekly basis, where before it would take a month. The local pool shop has tested the water for minerals only to tell me each time that it tests clear. I have been getting rid of the pool stain with acid but it always returns after about 2 weeks. I use a product that is supposed to remove the stain from the water and we clean the filter cartridge weekly. Can you suggest something that may be in the water that is causing this? Thanks.

Oz, Australia, 4/16/2008

It definitely sounds like a mineral stain. The fact that the local dealer is not testing positive does not preclude this possibility. Minerals can be present and because certain types of chemicals have been added by either the water utility or the pool owner, it is possible that the testing procedure is encountering interference. Iron is most likely the mineral causing the problem. I suggest that you treat the problem with a concentrated metal treatment, such as phosphate-free Liquid METALTRAP. In addition, to treating any iron and heavy metals, it will help keep scale deposits from forming on the salt/chlorine cell. The low pH approach is not a long-term solution. You could look into something that will make cleaning the filter cartridge easier: The Blaster.  I hope that this will prove helpful. Good luck!

Sincerely. Alan Schuster, 4/17/2008

Blue Stains and Black Spots?

We enjoyed your site and have made use of your suggestions on blond hair turning green. Now we have another problem. The top steps at each end of the pool and the sides of those steps have developed turquoise blue stains all over them. Why? Also, we are getting little black dots (or spots) on the bottom and sides of the pool. Here's a little history on our pool. It is a one year old, gunite and plaster pool, 13 X30, full sun and we started using an aluminum solar blanket this past March. We did not have this problem or green hair last season. It is not a heated pool nor is it connected to a spa. The only thing I know that I did wrong this year was to allow the chlorine level in the pool to run out for about one to two weeks starting Memorial Day. We also had the blanket on during this time as well and forgot to check the chemicals. (We do our own testing and maintenance). During this period the pool temperature hovered between 86 and 90 degrees. The blue stains only appeared on the step surfaces closest to the water surface. I also want to mention that our small filter, that we clean and check twice a week, has an Ionizer in it. Also, after discovering my chlorine snafu, I tossed 5 chlorine tablets into our floating basket, waited a week or two and then had the water professionally tested, after my wife's hair turned green. The testing showed the pool only needed a little muriatic acid and all the other levels were fine including pH. My wife's hair doesn't seem to be turning green anymore and if we scrub the blue stains with a pumice stone, some pool stains disappear with A LOT of elbow grease. No amount of  scrubbing takes the black spots off. Any suggestions? I hope that we havenít been overly windy. Thanks for any help that you can give us.

Miles P., Henderson, NV, 9/2/2009

The green hair and blue-colored pool stains could be from copper. The question remains, how much copper is detectable and, if the level is more than a few tenths of a PPM, it is very likely the Ionizer is providing too much copper. Check the settings or controls and review the operating manual. If there is no copper present, the green discoloration of the hair could be due to the chlorine reacting with hair products. The blue pool stains could be algae. The black spots could be algae, other minerals or a copper pool stain, in the presence of high calcium hardness levels. Try this! Place a 3" tablet of top of the pool stain and allow it to remain there for a few hours (the tablets can affect some masonry finishes, so either test it on an inconspicuous spot or verify suitability with the finish contractor). If the problem is algae, you should see improvement. If not, try placing a sock with a 1/2 pound of pH Minus on top of a stain. Shut the filter off and allow to remain in place for 15-30 minutes. If improvement is seen, the problem is minerals. Adding a mineral treatment product could interfere with the Ionizer. Check the manufacturer's recommendations on treating heavy metals, in a pool with an Ionizer. I hope that I have been helpful.

Sincerely. Alan Schuster, 9/3/2009

Ascorbic Acid Works. But?

Alan, I have a 30,000 gal gunite/plaster pool and read that you recommend shocking rather than ascorbic acid for tannin stains. I get these pool stains often (once or twice a year due to a large oak tree) and always remove them successfully with ascorbic acid. I would love to use the shock treatment for the ascorbic acid costs about $100 per treatment, but the shock treatment doesn't work for me. I shock once a week during the summer and once a month during the winter. Am I misdiagnosing and really have something other than tannin stains for which ascorbic acid also works? Thanks in advance.

Joe P., 5/28/2008

Chlorine destroys tannins. Plain and simple. If it doesn't work in your case, it is probably not tannins or tannins and a heavy metal pool stain. I realize the ascorbic acid is expensive, but MetalTrap Stain Remover works best against heavy metal stains. Follow with a dose of a phosphate-free, metal chelating agent, such as Liquid METALTRAP Add more Liquid METALTRAP prior to the addition of new water.  Once you remove the pool stains, you could do something that will help make sure there are removed permanently. Using the METALTRAP Filter, to treat all new water, helps keep new additions of iron and other metals out and minimizes the possibility of pool staining and pool water discoloration. You could, also, use The METALTRAP Filter to recirculate the pool water and lower the heavy metal content, already present in the pool water. It is definitely easier and, probably, less expensive in the long run. I hope that I have clarified the problem.

Sincerely. Alan Schuster, 5/28/2008

Amazing Reappearing "Rusty" Stains?

I live in South Florida. I recently acid washed my inground pool, which uses a copper oxidation electrode system rather than chlorine. The surface looked great and I refilled and balanced the pool; and then about 4-5 days later small rusty pool stains began to appear only on the shallow end. I was told that it may be rust leaching from impurities in the marcite surface, but I don't know if this is true. I can scrub them out manually with a scrubber stone but they come back. Is there anything I can do to remove them permanently?   I was thinking of spot painting over them because I don't want to resurface the pool. None of the pool centers know how to handle this because of the copper mineralizer system I have. I really need and would appreciate your advice. Thank You!

Mike F., Florida, 5/3/2004

There are problems with dark spots on plaster finishes, but this doesn't sound like that. It sounds like fertilizer granules. Is itSolar-Powered Mineralizer for pools. possible? The problem the dealer is having is that if you use a metal treatment, it may compromise the copper electrode function. The only way to treat the metals is to add a metal treatment. That will negate the copper algaecidal function, unless a suitable metal treatment is used. To provide algaecidal activity, you could use a polymer based algaecide for a few months, while the copper becomes re-established. This is one of the limitations in dealing with ionization-oxidation, Solar-Powered Dual-Ion Mineralizers or ionizers, that utilize copper, and having an existing heavy metal problem. You could use a MetalTrap Filter to lower the copper level, without compromising the ionization. A salt chlorine generator and mineralizer combination is a complete sanitizer and a much more affordable option.

Sincerely. Alan Schuster, 5/3/2004

The algaecide treatment and shock treatment, combined with chlorine tabs on each spot, successfully removed the pool stains. I also pressure washed to clear the top of the screen enclosure of debris. The problem is, after the pool looked great, when I went to bed. However, this morning new spots appeared, about 50 of them, in the same areas, but not the same spots. I have no idea what's going on, but I'm frustrated as hell. Any thoughts or suggestions? Thanks.

Mike, 5/5/2004

The pool stains are not copper or another metal or else the chlorine would not have removed them. The plaster spot problem that has been widely reported does not respond to chlorine. That only leaves algae or some organic type of pool stain. Have you ever added a metal treatment?  Is your pool overhung by a tree, such as a live oak or black olive? If chlorine was the solution, it seems that the oxidation function is inadequate, on a 24-hour basis. Perhaps, you should simply maintain the pool on a very low level of chlorine, so that there is always some present, for those times with active oxygen is not being produced. Using bromine would be even better, as it seems more effective against certain problem types of algae. It would be safe to assume that the copper is not able to control the problem, possibly due to the addition of metal treatments. Add a polymer algaecide and continue for a few months. I suggest that you shock the pool, raising the free chlorine level to 5-10 PPM. Use the brush and improvement should be forthcoming, in a day or so. Good luck.

Alan, 5/7/2004

Yes! There is a live oak above that area of the pool. Has that been known to cause this or similar problems? No, I have not used a metal treatment because the manufacturer of the copper system said not to. I agree it must be something organic, but damned if I know what it is, particularly since the stains show up so quickly.

Mike, 5/8/2004

Blame it all on the tree. As far as I am concerned the best live oak tree is a dead one. The same for black olive trees. I have a
Blue Diamond Robotic Pool Cleaner RC live oak in front of my house. It makes a mess of the lawn and stains the driveway. The state of Florida makes it difficult to take this native tree down. Certain times of the year the problems are worse. If you can legally take it down, I would do it. Your problem is this. The oxidation function produces forms of active oxygen that last only for a short time, after the unit is shut off. Leaves, seeds and bits of debris from that tree will leach tannins. Without an oxidizer or chlorine present, the tannins appear as rust colored stains. It has nothing to do with "iron rust" and it is not a metal pool stain. Tannins can be destroyed by chlorine and other oxidizers. You have several options. Get rid of the tree. Use a very low level chlorine as a backup sanitizer/oxidizer. Lastly, a robotic pool cleaner can micro filter and vacuum up the bottom, so that there is little or no debris to cause staining.  A Floating Pool Surface Skimmer would greatly reduce the amount of debris, that reaches the bottom.  This does explain why the stains keep reappearing!

Alan, 5/9/2004

Alan, hi! This is great because at least now I know what I'm dealing with. Before, it was a crap shoot. The tree is a neighbor's tree but branches hang over my pool and (with some difficulty I fear) I'm going to find a way to cut them back. I do use an automatic pool cleaner already and the tannin stains did only seem to appear in the six hours the motor was off at night. I'm grateful that at least we were able to diagnose the cause. Now for a solution! Thanks again!

Mike, 5/9/2004

Hi Alan, I followed your advice and had the tree cut back away from the screen enclosure. Shocked the pool, and the stains disappeared permanently! I plan on keeping a little chlorine present, just as a backup. Thanks so much for your patience and help. You have a great website!

Mike, 6/4/2004

Editors Note. In the final analysis it was simply a matter of there being no chlorine or oxidizer present during the overnight period. The problem was not attributable to copper staining. It was simply a matter of fine particles of live oak tree debris falling into the pool and leaching tannins, after the pool was shut off at night. The solution: maintain a low level of chlorine, with the copper-oxidation unit. 5/10/2004

Seeing Yellow?

I have a marcite pool that has been in for 8 months and it has gotten yellow-colored blotches on the bottom and the steps. The pH, chlorine, alkalinity levels are ok. I brush the pool each week. I was told the calcium would cause this. I have shocked it and I have put in a gallon of chlorine every two weeks.

Kendell W., Sarasota, FL, 3/12/2005

The yellow color of the spots could be attributed to several causes: iron pool stains, algae growth and discoloration caused by fertilizer granules. An Iron Test can measure the presence in the water. Try the following to help narrow the choices and point to a solution. Put 1/2 pound of pH decreaser in a white sock, shut off the filter and drop onto a stained area. Check after 1/2 hour. If there is a noticeable improvement, the likely cause was iron, in the water, or possibly fertilizer granules. Repeat this elsewhere, as needed to remove all of the pool stains. If the area is extensive, it may be necessary to drop the pH of the water to 6.5 or less. After the pool stains are removed, add a phosphate-free, metal chelating treatment such as Liquid MetalTrap, to help prevent a recurrence. Thereafter, add more of the product, prior to the addition of any makeup water. Restore the pH to 7.2-7.6. If the "sock treatment" did not work, the likelihood is that the problem is algae or even pool stains from leaves. Place a 3" chlorine tablet on a stain (NOT FOR VINYL POOLS), shut off the filter and allow to remain in place for a few hours (the tablets can affect some masonry finishes, so either test it on an inconspicuous spot or verify suitability with the finish contractor). If improvement is seen algae or discoloration caused the pool stain. You can use Polymer Algaecides, shock treatment and well-placed trichlor tablets (NOT WITH VINYL POOLS). Broader areas can be treated with a granular trichlor (NOT WITH VINYL POOLS). Calcium is usually associated with scaling or cloudiness. Yellow discoloration is not a characteristic of calcium. The discoloration is probably not related to any defect in the marcite finish. I hope that I have been helpful.

Sincerely. Alan Schuster, 3/12/2005

Staining Caused By A Black Olive Tree?

My neighbor has a black olive tree near our property line and a couple of times a years, it "drops" a lot of debris. Leaves and seeds get into the water and not all of them end up in the skimmers. The ones that fall to the bottom cause a brownish stain. Shocking will get rid of the pool stains, after I have removed all the junk. Is there anything else I can do. I hate that tree. Thanks.

Larry A., Boca Raton, FL, 7/17/2010

Remote Controlled Pool Surface Skimmer.
I have had the same problem myself. You are correct to shock after removing the "junk".  The stains are the result of Tannic Acid
leaching from the leaves. The pool stains occur after the leaves have remained in contact for a period of time. You might consider an automatic pool cleaner. It will help remove the leaves before staining can develop. It will help, but is not an absolute solution. There is no magic chemical. Another way to deal with troublesome leaves is to remove them, before they get a chance to sink to the bottom. A Remote-Controlled pool surface skimmer will make short work, scooping up all sorts of floating debris. It will reduce the staining, reduce the need to vacuum and even help distribute chemicals. Sorry that I couldn't be more helpful. 

Sincerely. Alan Schuster, 7/17/2010

Major League Mineral Problems?

Hi there Alan. First off, very informative site. I really wish I had found the site sooner in my endeavors, as it has become a real pool water problem-solver. This email is going to be fairly long, mainly because I don't know what is important and what is not. There are several questions/problems that I am having that will be interspersed throughout this narrative email. I will summarize them at the end of the email. If there is any information missing let me know and I will provide it.

BACKGROUND: We purchased a house that has an inground pool. It is a vinyl lined pool, 20x40'. Depth ranging from 3.5' to 8.0' (I'm guessing on the deep end, we haven't been in that side yet). We live in Londonderry New Hampshire . The pool water is currently 60 degrees and was 54 degrees when we opened it on May 3rd. The pool was covered with a winter cover that did get 2 rips which let in a little of the water that was on the top. The pool was professionally closed by the previous owners at the end of September. The pool has a DE filter. The pool has a main drain and one wall skimmer. There are 2 returns, one in the deep end and one in the shallow end. The home we live in is on well water and even after the softener still has higher than the preferred range levels of magnesium and iron (I can't find the closing papers so I don't know the exact after softener numbers.) The water going into the pool is before the softener. As such, I am sure the iron and manganese levels are in the 0.1-0.2 PPM range. I mostly use a solar cover and do not have a heater.

HISTORY: The pool was opened on May 3rd. I drained all water off of the cover, took off the cover, added approx 1.5 feet of well water. At this point I took the measurements with both the test kits with the little bottles and with the strips. Both tests were in agreement. The chlorine levels were in the range of 2.0 to 3.0 PPM. The PH level was much lighter than the lowest level on the scale. TA was 0. At this point in time I was misled by several websites (hence my statement earlier of "I really wish I had found your site sooner") and by a local pool supply store that the most important first thing to adjust is the pH. I have since learned the hard way that fixing the high minerals is the most important. I ended up putting in 30 pounds of pH Increase and this did nothing at all to the measurements. I went to several websites and found out from them that the single most important first item is to make sure TA is accurate. I am not sure of the total TA increaser I added, but I believe it was in the range of 30 pounds. I remeasured the levels and TA was at approx 40, ph did not move, and chlorine dropped a little. I then added another 20 pounds and TA did not really move. I then found 2 websites and a salesperson that said when this occurs shock the pool. I added 2 gallons of liquid shock. I don't remember the chemical name but it was the concentrated yellow liquid. The suggested rate is 1/2 gallon per 10,000 gallons. According to the directions I put in 1/4 gallon too much. At this point in time all was well, it was close to nightfall. The next morning I woke up and to my dismay the pool water was a green/orange/blackish color, all the fiberglass material (steps, returns) were a burnt brown color, and the walls were greenish in color. I tried scrubbing and power washing nothing took off the mess. 3 days later I ended up calling the local pool supply store and they asked if I had well water and when I responded yes they stated it was due to the minerals. I took my water measurements and the chlorine levels were still greater than 10 (not sure of the real level this was the highest level that the strips would go to). I went to the store and bought 4 quarts of mineral treatment. I asked about the high chlorine levels and was told not to worry about it. I did not agree with this believing that there was some reaction going on between the chlorine and the metals (again, I wish I found your site sooner). I then went to another pool store and they stated to be certain to lower the chlorine first. I bought 4 lbs of chlorine reducer and added approx 3 lbs of it. Within 10 minutes or so almost all stains on the walls and fiberglass were gone (one of the happiest moments in my short pool owning life). After the chlorine levels were down to approx 0.2, I then added the 4 quarts of mineral out at dusk, as the directions stated, left the filter running off of the main drain all night. When I woke up in the morning the pool was the sparkling blue color of before the super shock fiasco and no stains were present. I left the pump running, went to work and came home around 5. By this point in time the pool was back to green/black water color with green stains on the vinyl liner. The fiberglass was still clear. I figured that this was due to the merged metals and metal remover being captured by the DE filter and since I didn't backwash this bond ended up breaking down re-releasing the metals back into the water.

QUESTION -- QUESTION. Why did the water go back to green/black? I then added an additional 20 lbs of TA Increaser thinking that this might be the cause. The TA levels were brought up to 120. I went out and had one of the pool stores test my water. This particular place used test kits and not computer testing. The tests showed that my pH was lower than 6.0 and needed 20 drops to bring it up to 7.0, which was estimated to be 20 lbs of pH Increase. The CYA level was measured to be 50. Phosphates were 200 or so. I bought 4 more quarts of metal treatment and added it at dusk. Almost immediately after adding it the green/black water cleared up or so it appeared. I could almost see the where the metal out was moving through the water. I left the filter running again all night, this time vacuuming and backwashing in the morning. The pool water and walls had darkened a little overnight. By the time I had returned from work the water was a little darker. Not bad, but not the crisp blue that had been there before the shock and after the initial 4 quarts of metal treatment were added. At this point I figured the metals and discoloration were there to stay so I focused back on the pH.
ONGOING PROBLEMS: (2 days ago) I added approx 25 lbs of pH Increase and this brought the pH level to 7.3. (last night) I retested the TA and it was now close to 300. I figured since the pH was okay, that a high TA was not a point of concern. I then added chlorine to the automatic chlorine feeder. We are using the 3" trichlor hockey pucks. I intentionally set the level of feed low. I just wanted to get some chlorine in the pool to prevent algae from growing. (Today) I took a water sample to another store that does computer based testing and had them also run metal tests, including copper, manganese, and iron. What they found was that the iron and manganese were both around 0.1 and 0.2. Copper was non existent. pH was at 7.3. Free Chlorine was at 0.2. Total Chlorine was at 0.8. The disturbing part though is that both CYA and TA were off their measuring scales. I'm not sure what the upper level of their scales are. The sales guy told me that any CYA level above 100 is a point of concern and their testing platform stops testing at this point. QUESTION - QUESTION.  Is there any concern with the CYA levels being high?

QUESTION - QUESTION. Why would the TA and CYA jump dramatically like that?

QUESTION RECAP: When the water was treated with metal treatment and appeared to be resolved, why did the water go back to green/black the next day? Is there any concern with the CYA levels being high? Why would the TA and CYA jump dramatically like that? Nothing was added, as far as I can tell nor any of the people at the pool store, that would have/could have affected the CYA levels. It is possible that the original readings that I got were wrong with regards to the CYA. I'm guessing this because after 4 or 5 days after super shocking the levels were still measuring greater than 10. From what I was told, high CYA levels tend to lock in the chlorine levels. When I need to add well water next time what is the best approach? I see on your website a description of adding the metal out when adding the water. Should I go this route? Or should I just not use liquid shock? Is there any harm in adding too much metal treatment. Thanks in advance for your time and (hopefully) feedback. I did not intend to be so wordy but as stated earlier, I'm not sure what is important and what is not so I'd rather give too much information and have it be ignored than leave out the one piece of information that could provide the "ah-hah" answer.

Chris, New Londonderry, N.H., 5/16/2004

Not that I'm counting characters, but this may be the longest letter I have ever received. The first mistake was not adding a mineral treatment, as the pool was being topped off. Adding the label dose to your pool will never be adequate. The dosage recommendations are based on reasonably good or potable water quality: everything that your water supply is not! These mineral treatments will react with the iron and manganese. Hopefully you have added enough, but I would still add a dose or two every month or whenever new water is added.  Try and add the new water by placing the garden hose in the skimmer - give the filter a chance to remove some of the particles. D.E. filters are really good in this respect. An even better solution would been to use a pre-filter to help remove some of the sediments & metals and helps avoid problems. The acidic conditions helped to keep the minerals in solution. Raising the chlorine level oxidized the metals and decreased their solubility and increased their color value. The pool now has a good pH and high TA and CYA. So long as the pH is good and the water is clear and there is no sign of scaling, you may not have to lower the TA to 80-120 PPM. It depends on the calcium hardness reading and that was not provided. A high TA could result in scaling and cloudy water problems, if the calcium hardness is above 200 PPM. The high CYA level is due to the prolonged use of stabilized chlorine (tablets in your case). The tablets add cyanuric acid to the water as they dissolve. Levels above 150 PPM are thought to cause a decrease in the efficiency of chlorine. That means you need to keep somewhat higher Free Chlorine levels, if the CYA level is high. Given your water quality, I would not rush out to replace water at this point. In your area, water is normally pumped out to winterize the pool and this will put a cap on how high the CYA level can rise. I hope that I have addressed your questions. One of the CYA readings must be in error. The level could not change that quickly. Chemicals added to raise the pH, will increase the TA as well. After dealing with a mineral problem, it is a good idea to clean or backwash the filter: this avoids the possibility of the minerals being dissolved and producing a recurring problem. There is no problem adding more mineral treatment than needed. It remains in solution and available. In your case, more is better! Not all chemicals are the same, especially those without an ingredients statement. Some mineral treatments are more concentrated than others. Some degrade to ortho phosphate and are ineffective, if the pH rises to above 7.8. Good luck and enjoy the season.

Sincerely. Alan Schuster, 5/16/2004

Editors Note: it took a few days longer and a few more e-mails, but the pool finally cleared up. The problem was the manganese. Such a large volume of mineral treatment was required, because other minerals were present and were competing for the chelating agent.

Dual-Cartridge Filter System.
Editors Note: Years have gone by and treatment options have changed as well. The following is how that
pool should be treated, today. Inasmuch you are on well water, using the METALTRAP Filter, to treat all new water, helps keep new additions of iron and other metals out and minimizes the possibility of pool staining. You could, also, use The MetalTrap Filter to recirculate the pool water and lower the heavy metal content, already present in the pool water. Even better would be the use of the Dual-Cartridge MetalTrap Filter, which will remove metals, sediments and contamination. The use of phosphate-free, Liquid MetalTrap would have been a far better choice, than the product used, back then. It is a true chelating agent, is phosphate-free and is unaffected by pH. Why exchange a metals problem, for a phosphates problem?


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