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Manganese Pool Water Problems

A problem metal that causes staining and discoloration.
The Pool &and Spa Informational Website

Causes, Sources, Treatments and Solutions.


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!

One of the ColorQ all-digital, pool and spa water analyzers. 3588-01 Manganese Test Kit

Manganese Test Kit #3588-01

WaterLink SpinTouch Lab, for pools and spas.
METALTRAP Filters remove iron, copper and manganese. Stain Reversall Kit.
Dual-Cartridge Filter System. Manganese can be one of the most troublesome, of the heavy metals problems.  Detection is very important, as proper treatment can depend upon the actual concentration.  More common with sediment laden or well water.  Test and treat, as necessary, or stains will result. MetalTrap 1-Micron Pre-Filters for pools and spas.

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How to treat manganese problems in swimming pools? Manganese is one of the more troubling swimming pool mineral problems. This is especially true, if the water is sourced from a private well. Manganese shows up as a brown-black stain or discoloration and, thankfully, is not common in most areas. Purple stains or even crystal-clear purple water can occur, due to the presence of manganese. Corrosion of stainless steel (contains manganese) can lead to purple discolorations. In most cases the pool discoloration problem, is associated with the oxidation of the heavy metals, that are present in the water. Manganese can be treated with Mineral Treatment products (chelating agent). Higher than normal dosages should be used because of the likelihood that other minerals are present, but not necessarily detected. Stain avoidance treatment should be used, whenever a water analysis indicates even a trace amount of manganese is present. An alternative method of dealing with known manganese and heavy metal problems is to use the METALTRAP Filter, which can physically remove the metals, as the pool water is being added. If sediments are present in the source water, a METALTRAP Dual-Cartridge Filter will remove both the precipitated metals, as well as the dissolves metallic ions, greatly reducing the likelihood of staining and discoloration.  Manganese problems can treated with Pool Refresh, used in conjunction with other METALTRAP products. 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 and 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.
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.     ▼

Keeping Manganese Out Of The Pool?

Hi Alan.  I am looking for a filter that I can attach to an outdoor garden hose, that will remove manganese, when I need to add water to my pool. Would the MetalTrap 1-Micron Pre-Filter, model PS-PF for pools, work for that?  Thanks.

Paul C. 8/17/2018

Manganese can be a serous staining and discoloration problem. Manganese can exist in two forms: fine sedimeDual-Cartridge Filter System.nts and in the soluble, dissolved state. The MetalTrap 1-Micron Pre-Filter will remove all types of sediments, down to 1-micron, but will have no effect on removing dissolved manganese, copper or iron. It will help, but probably will not solve the problem. The MetalTrap Dual-Cartridge Filter is a better option and does connect to a standard garden hose. It use two different filter cartridges. The first is a 5-micron filter cartridge that removes sediments and is washable and reusable. The second cartridge can remove up to 1 PPM, of dissolved metals, from up to 28,000 gallons of water. If the level is over 1 PPM, it will treat proportionally less than 28,000 gallons. This cartridge is not reusable, but is replaceable. This product treats manganese, iron and copper, whether present as a sediment or in a dissolved state. I hope that this will be your solution.

Sincerely.  Alan Schuster, 8/17/2018

The Gardeners Caused Manganese Stains?

Our gardeners accidentally spilled some manganese sulphate into our pool when applying it to our pigmy palms. This has created some stains at the bottom of our pool. Which of the products listed is the best to use for removing these stains?

Doug H., 1/27/2017

The most common metals to cause staining are iron, copper and manganese. Manganese is the least common and usually the hardness to treat. Few dealers have the ability to test for manganese, to make matter worse. Simply adding a metal treatment is very unlikely to work. This will take a regimen. Before attempting the solution below, add a dose of a 60% polymer algaecide, to help maintain water quality, during the necessary absence of chlorine. The information below is based on 1 PPM of manganese, which is just a few ounces in 10,000 gallons of water. Should you find a dealerStain Reversall Kit. with a tester, it does not measure the manganese that already has precipitated and lead to staining.  Removing stains can sometimes be easier than keeping them from returning. The oxidized salts of metals such as iron, copper and manganese are much less soluble, than their reduced forms. By adding METALTRAP Stain Remover to a chlorine-free pool, it will solubilize the manganese, by converting it to a more soluble and less colored state. When the stains are gone, even though the water may be discolored, now is when you want to add POOL REFRESH-TOTALTRAP. This product will precipitate the manganese. for easy removal by filtration or vacuuming to waste. Use as directed. To prevent any manganese that might have collected in your filter, prior to treatment, clean of backwash the filter. Otherwise, you could be adding to the problem.  Once the POOL REFRESH and filtration/vacuuming to waste has solved the problem, add 1-quart of Liquid MetalTrap, for each 10,000 gallons. This will help scavenge up any remaining traces and prevent a recurrence. Wait a day or two, before starting to add chlorine. The amount required will be high, because it will be destroying the excess MetalTrap Stain Remover. The METALTRAP Stain Reversal Kit contains most of what is needed.  Manganese test kits are available, but are much more expensive that most other pool test.  I hope that I have been helpful. If so, please tell your friends and dealers about the website.

Sincerely, Alan Schuster, 1/28/2017

Manganese Stains?

I plan on filling a 16,000 gallon vinyl pool with water from my private well. I know that there is a low level of manganese in the water. How should I treat the water after I fill the pool up? I hope that you will be able to offer some advise. Sincere thanks.

Don C., Westhampton, NY, 7/14/2013

Fortunately, you know that there is manganese in the water. It would have been helpful to know how much. Testing for Iron
METALTRAP Filters remove iron, copper and manganese. and/or Manganese is very important is planning a successful treatment. Having lived on Long Island, I know what a problem manganese can be on the south shore. Those brown-black stains and discoloration are not great to look at. In addition to having manganese, it is likely that the water has iron and other minerals. Manganese is frequently associated with a purple discoloration or stain. The incidence of manganese problems, is for the most part, limited to well water or corrosion of stainless steel. Both iron and manganese can be treated along similar lines. The use of the METALTRAP Filter can help remove manganese and other heavy metals as the water is being fed into the pool. This will help prevent discoloration and/or staining, that might follow upon the addition of chlorine and other chemicals. Thereafter, use the METALTRAP Filter, when adding all new water. This preventative maintenance could spare you a lot of grief and the risk of unsightly staining. Good luck and enjoy the season.

Sincerely. Alan Schuster, 7/14/2013

How to deal with Manganese stains and problems.

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 Filters remove heavy metals. MetalTrap 1-Micron Pre-Filter, for Pools and Spas.
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.

Manganese or Magnesium?

I am confused about manganese and magnesium. What's the difference?

Ed. B., 8/14/2018

Magnesium chemistry is closely related to that of calcium. However, it is much more soluble in a swimming pool. It is not associated with any staining or colored pool water problems. Magnesium contributes to the TOTAL HARDNESS of the water
Stain Reversall Kit. and unless the water is very hard, there should not be a problem. Manganese is completely unrelated and is almost always the center of a staining and/or a colored pool water problem. Manganese is not common in municipal water supplies. However, in some areas, it can be present in well water. If manganese is suspected of being a potential problem, a water analysis will help determine the concentration. This is important in order to help assure proper treatment. In areas where the problem exists, dealers should test for manganese. Although manganese discoloration and stains can be treated with chemicals, such as Liquid METALTRAP and METALTRAP Stain Remover, the physical removal of the manganese and other heavy metals, helps assure that staining and discoloration will nor recur. The METALTRAP Filter can be used to remove metals from water, being added to the pool, and to recirculate the pool water to remove metals present in an already filled pool.  I hope that I have eliminated the confusion and been of assistance.

Sincerely. Alan Schuster, 8/14/2018

Manganese Test Kit?

Hi, Alan, I have a pool service business on the east end of Long Island. There is a manganese problem in some areas of the south shore. Is there a simple test kit that I could use, in the field, to test for manganese. It just might help solve a lot of problems for me. Thanks.

Tommy C., Quogue, NY, 3/19/2011

There are compact and portable field manganese test kits that are suitable for your needs.  Your
Liquid MetalTrap. customers will appreciate all the aggravation that you're are helping them avoid.   If you know manganese is present before the pool is filled, you can use METALTRAP Filter to remove much of the manganese and iron. It should remove it all and can make a huge difference. Thereafter, it should be used to treat all new water, as it is being added. It simply attaches to the garden hose, being used to add the water. I hope that I have been helpful.  One more word of advise.  Add 1 dose of a true, phosphate-free chelating agent, such as Liquid MetalTrap, for each 0.5 PPM of manganese found.  This product works over a wide pH range and should help deal with other minerals that might, also, be present.  Have a good season.

Sincerely. Alan Schuster, 3/19/2011

Keeps Coming Back?

My well water does contain a small amount of manganese. I add a metal treatment, on a regular basis, but the problem keeps returning. I have a salt chlorine generator and have never used a copper or silver algaecide. Is there a solution, as I feel that I am on a merry-go-round. Thank you.

Jeff B., Michigan, 7/30/2011

Stain Reversal Kit.
The high pH that results from the salt chlorine generator will make metal treatments, containing organic phosphonic acid, less
effective. In addition, they degrade, over time, forming ortho-phosphate: which can add to algae woes and require phosphate removal. Every time you add water, you are adding manganese. If you used a METALTRAP Filter to treat all new water, you would keep the manganese out of the pool and that is as good as it gets. Adding Liquid METALTRAP will chelate any manganese and other heavy metals, present in the pool water. Unlike most other metal treatments it is phosphate-free and is unaffected by higher pH readings. If staining is present, it can be dealt with, using METALTRAP Stain Remover along with the liquid METALTRAP. I hope that this information helps clear up the problem.

Sincerely. Alan Schuster 7/31/2011

What To Do?

Hi Alan. How do I remove manganese from my pool? Is it toxic? Thanks.

Phil, Australia, 12/22/2009

Are you sure it's manganese? It is found in some well water. You are not going to remove manganese from the water. At best you will be able to control the staining and discoloration problem that could result. Many products use the work "remove" very
METALTRAP Filters remove iron, copper and manganese. liberally, when they really mean "helps control." For each 0.5 PPM, add a dose of a quality metal treatment, such as phosphate-free Liquid METALTRAP. Add at least a double dose. Adding it with the pH lowered and a low chlorine level might help the product work better and faster. Allow 6-8, with the pump running. If there are any signs of staining or discoloration, repeat the dosage. If there is manganese present, there could be other metals competing for the metal treatment and there could make additional doses necessary. Thereafter, add another dosage monthly and prior to the addition of any new water. When adding water, place the hose in the skimmer, as this will allow the filter to have a chance to remove any particulated minerals. While is not toxic in a swimming pools at low levels, it could fail to meet the standards for drinking water. If there is doubt, check with the local water authority or health department. Manganese can be a tough problem. A better solution, to avoid future problems, would to be use a MetalTrap Filter to treat all new water added to the pool. Nothing beats keeping the problem out of the pool. Good luck and I hope that I have been helpful. Good luck and I hope that I have been helpful. Happy holidays!

Sincerely. Alan Schuster, 12/22/2009

Thanks Alan. Yes I'm sure it's manganese. It came in the last batch of salt I put in. I will follow your directions and see how it goes. Great site you have -Very helpful.

Phil, Australia, 12/22/2009

It would appear that you used a technical or industrial grade of salt with your salt chlorine generator. That was a mistake. Try to use only a food grade or water softener grade. No rock salt or salt with yellow prussiate of soda! At least you'll know for the next time.

Sincerely. Alan Schuster, 12/22/2009

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 in color, 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., 5/2/2007

THIS IS DEFINITELY NOT AN ALGAE PROBLEM! IT IS DEFINITELY A MINERAL PROBLEM!. The action of the chlorine turning the discoloration 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 color of the pool water and the colored staining can be indicative of manganese. 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
Stain Reversall Kit. 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, can cause dark or black stains, under certain conditions. The blue-purple color could have been a faint deposit of copper, normally bluish in color, and the background color of the pool finish. 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 deposits 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 mineral treatment, such as phosphate-free Liquid MetalTrap, to help prevent further staining and discoloration. Raise the water level above all of the discoloration. Add muriatic acid until the pH has dropped to below 7.0. 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 stains. METALTRAP STAIN REMOVER, can help in removing the stains and can be added to the acidic pool. This material will react will 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 stains are removed, add another 2-3 doses of a Liquid METALTRAP, before restoring the pH. It will be necessary to shock the pool, in order to destroy all of the remaining 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. Refer to other related topics in the archives. I hope it works out for you.
Sincerely. Alan Schuster, 5/2/2007

Thank you Alan. Yours has been the first sensible response I have had. It does come off with the sock & 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., 5/2/2007

The purpose of the bypass was to minimize corrosion. Clean the filter out before treatment and again afterwards, so as not to redissolve what you are trying to remove from the pool walls. Don't neglect to add the mineral treatment! Otherwise, you could get a recurrence. You can swim as soon as you restore the pH and the chlorine levels. Inasmuch as the stain was removed without the oxalic acid, I don't see the need to add the product. It seems that things will work out for you. Good luck with the sale of the house.

Sincerely. Alan Schuster. 5/2/2007

Purple Problems?

Is their a way to get rid of manganese in our pool without turning everything purple and having to brush, vacuum, and clean the filters. We use chemicals from our local pool dealer and we keep having purple results from the metals out chemical. I have contacted the chemical company and they said that the only thing that would cause their product to react in purple would be manganese. The supposed pool Dr. from this area of the country, said that this is becoming an epidemic. (Manganese in pools) We have a steel manufacturing plant within 20 miles and a many refineries within 30 miles. Could this have something to do with our manganese problem?

Sandy P., 5/6/2014

Manganese does not come up often, as a problem, so I doubt it qualifies as a new epidemic. Still, if you have to deal with manganese, it
Manganese Test Kit is a real problem. The source is usually well water. A manganese test will confirm the present and concentration. I have seen concentrations so high, that it was suggested that water be trucked in. If you are using municipal drinking water, it is not likely to have a concentration over 0.5 PPM. It is treated on the same basis as iron.  It may take more chemicals and time and knowing the extent of the problem will help. I would add a dose for each 0.1 PPM of manganese, because of the purple reaction. The metal treatments will work better, if the pH is under 7.0 and there is no chlorine present. Wait 1-2 days, after treatment, before raising the pH and restoring the free chlorine level. Usually, if manganese is present, other metals are there, as well. Have the water tested for iron and copper and add extra doses, for each 0.5 PPM found. Not all brands are the same and some contain phosphates, which can lead to other problems. The combination of Liquid METALTRAP and METALTRAP Stain Remover can provide effective treatment. Used with the METAL TRAP Filter, it can physically remove the metals from the pool water and can be to treat new water, being added to top off the pool. Stay away from bargain brands. Good luck and I hope that this information is helpful.

Sincerely. Alan Schuster, 5/6/2014

Lots Of Manganese?

I have a 97,000 litre pool with a salt chlorinator. Due to local drought conditions in Australia, I now have to use bore water to keep the pool levels for continued use. (My property is on the market). The bore water has Manganese concentration of 2.6 mg/l. The chlorine now produces a black and unsightly precipitate. Alan, is there a product that can be added to the pool water or skimmer box to cope with the manganese problem? What other advice can you give me regarding same? With thanks.
Chris B., 9/13/2007

That is about fifty times the concentration in marginally drinkable water. I would use a metal removing pre-filter to process all
Dual-Cartridge Filter System. new water. It will remove some of the particles and reduce the problem. Otherwise, treat it like iron, but use a higher dose of a quality, phosphate-free metal treatment, such as Liquid METALTRAP. At least one dose per 0.5 PPM. Having a DE filter will help. Add another dose monthly and prior to adding new water. A simple and effective way to reduce most minerals problems, resulting for the use of well water, is to use the METALTRAP Filter. This attaches to a garden hose and removes the manganese and other heavy metal mineral content, that would get into the pool. otherwise. Makes it easier to treat the pool. Use the METALTRAP Filter or Dual-Cartridge METALTRAP Filter, every time new water is added, for best results. I hope that this information will prove helpful.

Sincerely. Alan Schuster, 9/13/2007

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