Pool Algae Control Products

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Algae Control Products have evolved to more than just the traditional algaecides. The familiar algaecides include such active ingredients as: Quaternary (Quats) Ammonium Compounds, Polymers, Chelated Copper, Silver Compounds and various combinations. Phosphate Eliminators based on Lanthanum can be used to help "starve" algae into submission. Products based on Sodium Bromide or Ammonium Sulfate are being used to help control and eliminate problematic types of algae, mold and slime. Choosing the right product is important because effectiveness can vary based upon the problem and the water chemistry. In addition to proper sanitation, good circulation is a must to help prevent algae growth in areas with stagnant water or dead zones.  The use of The Circulator, as a replacement for standard return jet fittings, can dramatically improve circulation, better distributing sanitizer to all areas of the pool.  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 sanitation or water clarity, testing allows you to better understand the chemistry and determine the cause of the problem.  Once understood, you can 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.

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► White Spots Remain, After Black Mold Treatment?

We have a 16,000 gallon gunite pool colored with light grey plaster. It is 3 years old and we are located near San Antonio, TX.  Last winter we got some black mold in shade areas. We bought a black mold chemical online. It worked great but left lots of white or bleached out specs discoloring the service. It is not scale but discoloration. They are small in size such as 1/4" but sadly there are lots of them.  Any suggestions?  Thank you.

Jan L., San Antonio, TX 9/15/2018

It sounds like you added trichlor granules, which are about 90% chlorine, acidic and slow to dissolve.  Your description suggests that the surface was etched and that the gray colorant was destroyed.  If this is the case, it is not reversible.  Most likely the mold/algae grew in that area, because circulation was poor and sanitizing chemicals were not being delivered, to that area.  Dead zones promote growth of algae or mold.  Improving circulation is an important step, in help prevent a recurrence.  The Pool Circulator replaces standard return jet fittings and turns the return flow into a spiraling pattern, which reaches areas throughout the pool.  This delivers sanitizing chemicals and makes algae/mold growth less likely, by improving chemical distribution.  Acid washing the pool, MIGHT soften the color differences.  I hope that this information will be helpful. 

Sincerely.  Alan Schuster, 9/15/2018
 

► Algaecide Choice With A Salt Chlorinator?

We have a saltwater chlorine generator and have been delighted with its convenience and low operating cost, not to mention avoiding the hazards of chlorinating chemicals. We have gotten conflicting advice on the proper algaecides. Some say copper compounds are fine, others maintain that their use will damage the electrolytic cell by plating out metallic copper on the electrodes. My long-ago college chemistry courses suggest that plating is a possibility. What is your take on the matter. Thanks!

George H., 12/18/2020

Good old college chemistry! If your salt chlorine generator is self cleaning, scaling and plating are usually not a problem. Except in very hard water situations, I would not recommend a copper algaecide. You should be able to use any algaecide that is suitable for use in a chlorine pool. I would not use the sodium bromide algaecides, as they can shorten the life of the salt cell, by increasing the amount of chlorine that needs to be produced. A polymer formula product, would be my personal choice, as it is non-foaming and non-staining.  Algaecide use is less likely to be required, if a salt chlorine generator is used properly, to best effect.  I hope the information is helpful.

Sincerely. Alan Schuster, 12/19/2020


► Added Too Much Algaecide?

Dear Alan, we dropped a bottle of algaecide into the deep end of the pool. Our 10,000 gallon (marcite) pool now has 16 ounces of a copper based algaecide instead of 2 ounces. We have tried partially draining the pool and refilling, running the filter 24 hours, and of course, cleaning the filter. We still have an amazingly green pool and our neighbor said the pool will stain too, but he didn't have any answers. Our pool store, well, hasn't been overly helpful. Do you have any advice? We haven't found any other questions like this online yet. Can you help?

The N. Family, 5/25/2010

Just because you added too much doesn't have to mean that problems will, inevitably, result. Today, virtually all copper algaecides are based on chelated or complexed forms of copper: the purpose being to avoid staining and discoloration. In order to reduce this possibility, because of the overdosing, you should add 1-2 doses of a quality mineral treatment, such as phosphate-free Liquid METALTRAP, soon as possible. These products are formulated to chelate (complex) heavy metals, such as iron or copper. Once added the possibility of adverse effects should diminish. Another better option is to us a METALTRAP Filter and some garden hose and a small submersible pump. As the water is recirculated, the copper will be removed. Stop when the copper levels drops to a safer 0.3 PPM. Good luck and I hope that I have been helpful.

Sincerely. Alan Schuster, 5/26/2010


► Recurring Mustard Algae?

I think that I have a greenish mustard algae. It can be vacuumed and brushed quite easily. Shocking the pool does seem to help. The problem is that it comes back again and again. My pool is an 18 x 36 foot vinyl pool. What products are best to use so that I can avoid this problem? Thanks.

Floyd D., Brunswick, GA, 7/23/2013

Mustard algae can be treated in two effective ways and, in your vinyl pool, both are good. Chelated Copper Algaecides are effective in controlling this type of algae. The chelated types of copper algaecide will require additions every week or two and this will certainly help, in your case. Your sanitizer level, chlorine I assume, is probably not being maintained adequately at all times. Make sure that you maintain a 1-3 PPM level of Free Chlorine, at all times. Do this and it is unlikely that you will see the mustard algae problem returning, with any regularity. Consider adding an automatic pool vacuum, of some type. These cleaners are very effective at cleaning and improving the water circulation on the bottom, while operating. Another effective treatment for mustard algae is the use of a 60% polymer algaecide.  When shocking a pool make sure that you add enough product and it is added frequently enough to boost the Free Chlorine level to 5-10 PPM. Make sure that the pH is 7.2-7.6. Try to maintain at least 1-3 PPM, through the overnight period. Keep the filter operating continuously, until the problem is controlled. Once the problem is controlled resume normal chlorination and filtration. Poor circulation creates dead zones that promote algae growth. Better circulation assures better distribution of the sanitizing chemicals and makes algae problems less likely. The Pool Circulator is an easy-to-install device that will dramatically improve circulation and eliminate any dead spots.  I hope that this information will prove helpful.

Sincerely. Alan Schuster, 7/23/2013
 

► About Sodium Bromide?

I am looking to find some info on Sodium Bromide. I am a pool professional and I know it works for killing algae, yet I don't know what the actual process is for killing it. I have been told everything from it opens up the algae to let the chlorine kill it to it enhances the chlorine and gives it faster and stronger killing ability. Please let me know. Thank you.
 
Mike in San Diego, 5/20/2008

You gave me about 5 reasons and all are incorrect. It is really not that complicated.  When you add the sodium bromide and follow with a shock treatment, the bromide is converted into hypobromous acid: the active sanitizing form of bromine. Certain types of algae such as yellow-mustard algae and bacterial conditions such as water mold or "pink" algae appear to more vulnerable to bromine than to chlorine. These problematic conditions, that seemed resistant to shock treatment, are usually controlled and eliminated by the action of bromine. It doesn't necessarily work, as well, against all types of algae and bacterial conditions, but against certain chlorine-resistant problems it is very effective. While it will help solve the problem and make the water smell and be less irritating, it will increase the chlorine usage. The recommended maximum level of sodium bromide is 6 PPM, when used in outdoor pools, due to the potential of sodium bromate formation, at high sodium bromide levels. I would look into the use of alternatives, such as salt chlorine generators, ozonators and ultraviolet sterilizers. I hope that I have shed some light on the subject.

Sincerely. Alan Schuster, 5/20/2008


► Copper Algaecide Use?

I have been using a copper algaecide and our water is extremely clean. However, our stairs develop a yellow stain (it comes off, but keeps returning every few days). Could this be a result of the product? Also, I have researched copper sulfate, and the results indicate it should not be used in pools at 100% concentration. However, the Canadian government has okayed the use of this copper algaecide and deemed the 4% concentration acceptable. Do you agree? I want to keep using the product as is greatly reduces the upkeep. Thanks and great web site!

D.T., Windsor, Ontario, Canada, 8/11/2012

Copper sulfate should not be used in a pool!  You are not using copper sulfate. The product is a chelated copper algaecide that contains 4% elemental copper. It is in a form that is safe to use and helps avoid staining and discoloration. This product and all other swimming pool sanitizers are subject to government regulations, both in Canada and the U.S. In order to continue manitai9ning good water condition, you should maintain a proper level of a sanitizer such as chlorine or bromine. The use of algaecides provide an additional layer of algae control. The Pool Circulator is a circulation booster insert, that dramatically eliminates dead zones and makes the water come alive. You'll get better distribution of sanitizers and that should help minimize algae and other related problems.  I hope that I have been helpful.

Sincerely. Alan Schuster, 8/12/2012


► Freshly Finished Plaster Pool?

Could a maintenance dose of 1.5 oz a copper algaecide every other week for algae control could have caused staining or gray streaks? The plaster was about 2-3 months old, when added. Thanks.

Lenny M., 10/29/2017

The use of copper algaecides should be avoided in gunite pools, for at least 6 months after the pool was been plastered. This allows for the surface to completely cure. Otherwise staining is a possibility. If you want to use an algaecide, I would suggest a polymer formula, as it is both non-metallic and non-foaming. You should be able to remove the stains and restore the appearance, using a MetalTrap Stain Reversal Kit, which contains everything required to dissolve the stains, eliminate the stain-causing metals from the pool water and help prevent a recurrence.  I hope that this information will prove to be useful. If this website was helpful in providing information, please tell your friends and dealers.

Sincerely. Alan Schuster, 10/30/2017

► Clear Pool Water, But No Chlorine Reading?

I believe my pool dealer had me try 5 lbs of sodium bromide, a week and half ago. After adding 4 more gallons of liquid chlorine, I finally got rid off the persistent algae problem. The weird thing is it's crystal clear. No slime on the walls or under the water and no haze. The test kit shows no chlorine and I am concerned. I have a 3 inch tablet floating and I put 1-2 cups of granular in daily. Any suggestions on why?

Peggy, 6/14/2016

The mystery is over.  The addition of the sodium bromide converted the pool to a bromine pool. All the chlorine is being converted to bromine. Evidently, the type of algae you had was not responding to chlorine and this chemical addition helped to solve the problem. The goods news is that the water will feel and smell better. The downside is that it is a bromine pool and it is no longer protected against the Sun's UV rays, as is stabilized chlorine. Your usage will continue to be higher, until the bromides dissipate over the years or the water is replaced. Your water is now clear and chlorine wasn't working, so this is an improvement. I suggesting adding chlorine, after the Sun's goes down. Liquid chlorine would be the most cost effective and unlikely to cause long term buildup problems. To reduce the pool's overall chlorine/bromine requirements, I would add a 60% polymer algaecide, which an be used with chlorine or bromine and will help provide some sanitation, especially when the chlorine or bromine level bottoms out during the height of a sunny day. You've changed the way the pool is being sanitized and can make the best of it and get even more pleasant swimming conditions, as a result of this change. Adding The Circulator will dramatically improve circulation and chemical distribution and should make a positive improvement.  It simply replaces standard "eyeball" return jet fittings.  I hope this puts your mind at ease. Enjoy the season.

Sincerely. Alan Schuster, 6/14/2016


► Should I Add Algaecide?

I had a vinyl inground pool installed last fall and it was opened this spring for the first time. The water is under control and clear. Is there a need to add algaecide as a preventative measure or should it only be added when necessary/required? Thanks.

Michael, Montreal, Canada, 5/10/2017

The best time to actually add an algaecide is before you need it. That way, perhaps, you won't need it. It is arguable that if you maintain proper control of the water chemistry, an algaecide is not necessary. I would never go out of my way to add a quat algaecide: dimethyl benzyl ammonium chloride, as it can cause foaming and interfere with DE filters. A polymer algaecide is always a good choice, but it is expensive. Copper algaecides are cost effective and are, generally, a good choice for a vinyl pool. In short, take care of the water and the algae should not be a problem. If you maintain a consistent and adequate level of free chlorine, the need for algaecide is diminished. Adding a salt chlorine generator might be a step worth taking. It is the better way to do chlorine. No handling, no measuring product and no storage. Enjoy the season.

Sincerely. Alan Schuster, 5/10/2017


► Which Pool Algaecide To Choose?

I was in the pool store the other day to pick up some algaecide. I couldn't believe the number of different types. The prices went from about $5.00 to over 20 bucks. How do I know which one is best for my pool? A 24' above the ground pool. Thanks.

Charles H., Clearwater, FL, 6/12/2008

You're right there are a lot of choices. Here's an illustration: if you're sick and need an antibiotic, taking aspirin won't necessarily help. Some algaecides are cost effective and can be used to treat the everyday varieties of algae: "quat" and chelated copper algaecides are in this category. Others algaecides are more costly, but are highly effective in the treatment of resistant algae problems: Polymer (polyquat) and Silver Algaecides fall into this category. Being that your above ground pool is vinyl, I suggest that you consider a chelated copper algaecide: this product is very cost-effective and provides excellent results against blue-green and yellow-mustard types of algae. If in the future, you encounter a resistant type, a switch to another product can be made.  I hope that I have been of assistance.

Sincerely. Alan Schuster, 6/12/2008


► Borates And Algae Control?

Hi Alan. Great web site! What is your opinion on the use of sodium tetraborate for algae control in an inground pool? I believe the release of boron into the water prevents algae from growing or so they claim. It also spikes the pH up quite rapidly, which is why they sell it in a kit form which includes proper amounts of pH down material.

Tim C., 4/2/2007

The borate products work by lowering the levels of carbon dioxide in the pool water. Low levels impedes algae growth. The pH is just over 9, so that is why pH reducer must be added. There is little doubt that this product can help in the control of algae. However, you will still have to maintain a proper sanitizer level, for ideal pool conditions. For those times when the chlorine level bottoms out, this product might provide some leeway. If you could maintain adequate chlorine levels at all times, you might not see a significant benefit from this product. Most chlorine products are added in a intermittent basis or haphazardly and, under those circumstances, borates add an additional safety margin. However, newer sanitizing methods such as salt chlorine generators maintain excellent control of algae by providing a steady, adequate and almost effortless application of chlorine to the pool. If you are looking towards improving algae control and water quality, I would look in this direction. I hope that this information proves helpful.

Sincerely. Alan Schuster, 4/2/2007


► Vinyl Pool Algaecide?

I have a inground pool with a vinyl liner. I have been told conflicting ideas about algaecides. Can I use any type of algaecide with a vinyl liner? One company told me I needed to buy a more expensive algaecide for pools with a vinyl liner. Is this company just wanting to charge more for a more expensive product? Is any algaecide ok to use with a vinyl liner? Thank you.

JR, 5/3/2007

Every algaecide on the market is used with vinyl pools, so far as I know. If your water contains iron and other metals, I would not use copper algaecides. If the water is very hard, I would not use copper algaecides. Otherwise, a quality copper algaecide is very cost effective in a vinyl pool. I would not use algaecides that contain dimethyl benzyl ammonium chloride or similar sounding names, in any pool, because they usually lead to foaming problems and are not always effective. They are inexpensive and that makes them popular. Sometimes, when functioning as a wetting agent, they make of algaecidal treatments more effective. Polymer algaecides are expensive, by comparison, but they work well, do not foam, can't stain and can be used in all types of pools. Price limits their popularity. Silver algaecides are relatively expensive, but effective. There are some staining issues, but usually not in a vinyl pool. The best algaecide is one that works. Your call-your budget! I hope that I have helped you better understand the choices and differences.

Sincerely. Alan Schuster, 5/3/2007

► Algae Control Without Foaming?

We just moved into a house with an in-ground swimming pool. Our old house had an above-ground pool. One of the things that I disliked about the old pool was the foaming caused by using an algaecide. I don't want problems to ruin the look of this pool or end up with green water. Are there algaecides that don't foam? Willing to listen.

Frank R., Wayne, NJ, 7/17/2012

Actually, there are algaecides that do not cause pool water foaming.  The best choices are: polymer (polyquat) algaecides or chelated copper algaecides. The polymer algaecides are more expensive, but are highly effective against most types of algae. The chelated copper algaecides are very cost-effective and are excellent in vinyl pools and for use against the common varieties of algae, as well as mustard algae. Most algaecides will help solve problems with green water. While it is true that the very common "quat" algaecides do have a tendency to cause the pool to foam, it is not normally problematic or unsightly. In those instances, where unsightly pool water foaming is occurring, it is highly probable that there is an air leak in the suction lines. A pinhole-sized leak can allow air to be sucked in and this, in turn, leads to aeration and foam. Something worth checking into?  I hope that I have been of assistance.

Sincerely. Alan Schuster, 7/17/2012

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