Phosphate Problems in Pools

Optimizing chemistry, improving circulation and eliminating phosphates!!!

When the water contains phosphates and the chemistry is out of balance, the likelihood of algae growth increases. Algae is always present, to some extent, waiting for the right opportunity.  Water chemistry and proper sanitation are the first lines of defense.  A ColorQ, All-Digital Water Tester can perform all of the common pool water tests, eliminates the color-matching and guesswork.  There is a model, for every pool testing need.  Reliable water testing will help solve and avoid problems.  Better Circulation helps make everything work more effectively. The Circulator is a return jet replacement fitting, that improves filtration, eliminates the dead zones that promote algae growth. Adding TotalTrap-Pool Refresh will allow you to vacuum and filter out phosphates and make algae control more effective.  Phosphates and Nitrates can increase the growth of algae, as both are vital plant nutrients.  Nitrate removal is not practical, but phosphate removal is easy enough to do.

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Alternative Pool Water Sanitizers

When phosphates are a frequent problem, it is imperative to maintain proper sanitation.  Adding some backup sanitizing is important, as chlorine levels rise and fall, based on pool usage and chemicals being added.  Most pools use some sort of chlorine.  A Salt Chlorine Generator is definitely a better way to do chlorine.  Salt chlorine generators are highly automated and give you better control.  In-Line and no-installation-required models are available.  An Ultraviolet Pool Sterilizer kills 99.9% of the microorganisms, passing through the cell.  It can kill sanitizer-resistant pathogens and is typically used with chlorine or bromine.

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How to treat Phosphate problems, in pool water?

 Phosphates can increase the likelihood growth of algae in swimming pool water and can enter the water from such sources as: decaying plant matter, fertilizers, mineral treatment chemicals, contaminated well water, acid rain, contamination with soil, ground water runoff, bird droppings, bather wastes, urine and sweat. It is not realistic to expect phosphates to remain very low, indefinitely.  While under 0.3 PPB (330 PPM) is optimum, under 1000 PPB (1.0 PPM) is much more practical, when normal algae control is maintained.  Phosphate is a vital plant nutrient and the presence in swimming pool water, even at low concentrations, can cause accelerated algae growth in poorly maintained pools. Pools, that are properly maintained, usually do not have unexpected difficulty controlling algae, even in the presence of phosphates. Higher levels of phosphates can make algae control more difficult and increase the amount of sanitizer required to maintain satisfactory control of algae. It is possible to remove modest levels of phosphates, by treating the pool water with a phosphate eliminating product, such as POOL REFRESH. Very high levels may require so much of the precipitating compound, as to render this approach impractical, unless there is no option of water replacement. In order for phosphate reducing products to work the concentration of phosphates must be reduced to extremely low levels: parts per billion. The benefits of such product use is adding another layer of protection against algae growth. Proper pool water maintenance is always the first line of defense. Testing for phosphates is not universal, but in those cases where algae control is proving difficult, despite apparently ideal pool water conditions, testing for phosphates and nitrates might be advantageous.  You may not be able to remove nitrates, but removing the phosphates is the next best thing, as both are vital plant nutrients.  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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► Can't Maintain A Chlorine Level?

I am having a problem with my pool. I cannot get a free chlorine level, and have found high phosphates in my pool. I have used about 3 phosphate treatments. in different strengths, over the last 2 weeks, and still have a high Phosphate level. I have read up enough on the issue, but part of the problem is that I only can currently test to 1,000 PPB. I have been searching far and wide, and cannot find a test kit that will test very high levels of Phosphate. I purchased the house 2 years ago, and have been having problems from the beginning, and I assume it is from this high phosphate level. I will gladly continue using phosphate removers to get it down, but I would like a test kit that tests high enough to show if it is working at all, or not. Thanks for your help.  Regards,

John D., 7/23/2020

You can have phosphates present and still maintain a chlorine level - it make it less forgiving, but it is doable. I think the inability to maintain a chlorine level, is that the pool might have used bromine or a sodium bromide algaecide, in the past. If this is the case, when you add chlorine, it is quickly used up, as it converts the bromides to bromine. The tests for both are the same, so you see no immediate difference. Cyanuric acid protects chlorine from destruction, by the Sun's UV rays. Nothing can protect bromine and the levels drop quickly, during daylight hours. Try adding chlorine, after the Sun goes down and see if that doesn't at least allow a reading to persist, until dawn.  If the pool is showing signs of visible algae, it might simply be that you have not added enough to eliminate the algae and slime deposits, on all underwater surfaces. There is no way to eliminate bromides, short of water replacement. Phosphate Test Kits typically read to 1000 PPB (1 PPM). However, you can work around that, if levels are higher. Mix one part of pool water with 9 parts of DISTILLED water and test the mixture. Multiply the result by 10, for an accurate reading.

The phosphates just didn't get there overnight. A level could have been present, since the pool was filled. Yet, there may not be any visible algae growth, as the present of phosphates doesn't make algae growth inevitable. It does, however, make the failure to maintain proper free chlorine levels less forgiving. Without a doubt, it is best to have zero phosphates. But, that is not always possible or practical. A level of 100 PPB is considered to be the best obtainable, under normal circumstances. It is difficult to maintain this level and even several hundred PPB should be manageable, in terms of algae control. You can add a phosphate remover, such as POOL REFRESH, to drop a reasonably high level down to a level that should not act as a stimulus for algae growth.  If this website was helpful, in answering your question, please consider joining our E-Letter Mailing List.  You'll receive E-Letters, with helpful information, new product updates, suggestions and sale announcements. I hope that this recommendation works out for you.

Sincerely.  Alan Schuster, 7/23/2020
 

► How Do Phosphate Eliminators Work?

A local pool store suggested a phosphate eliminator, as means of controlling algae. What actually is a phosphate eliminator?

R. Z., Portland, OR, 6/11/2014

Phosphate eliminators are based on chemical compounds, that cause the phosphates to precipitate from the water. These products reduces the phosphate concentration from parts per million to parts per billion.  Phosphates are a necessary nutrient for algae growth and their nearly total removal from the water can impede their growth. The phosphate eliminators can be used with chlorine, algaecides and most pool chemicals. Used properly and in conjunction with sanitizers, phosphate eliminators can add another layer of algae control. They must be added periodically to keep the phosphate levels depressed, because swimmers and their associated wastes are a source of new phosphates. A new and better way to remove phosphates and heavy metals, at the same time, is with the POOL REFRESH system. Just add the combination, of two products, to the pool and let the pool filter and or vacuum get rid of the problem. A Phosphate Test can be performed occasionally to determine the need to add additional product.  To better assure proper overall pool water chemistry, visit a pool store that has a very reliable, professional lab such as a WaterLink SpinTouch Lab, rather than a less accurate test kit or strip reader.  I hope that our website has been helpful.

Sincerely. Alan Schuster, 6/11/2014


► Phosphate Problems With Well Water?

My well is adding phosphates to our pool via the auto-fill. Will your Fresh Start product capture the phosphates or just metals? If so, can I attach it to one inch PVC line? Do you have another suggestion or better idea if I am going down the wrong path? Thanks.

Darren B., 12/3/2020

Most likely the well water contains iron, as well. I would use a METALTRAP Filter, to treat all new water being added to the pool. This will remove iron, copper and other heavy metals, from all new water additions. It won't remove phosphates. To do that you can add the POOL REFRESH system, to the pool. It will precipitate the phosphates and heavy metals, so that they can be vacuumed and or filtered out. When the filter is cleaned, these problematic minerals are out of the pool, permanently.  Test the water periodically, to see if any follow up treatments are necessary. I hope this information will help solve the problem.
 
Sincerely. Alan Schuster, 12/2/2020

► Phosphate Eliminators And Algaecides?

Every now and then I get a touch of a greenish water and algae. Some algaecide and shock, is all that it seems to take. Is there some advantage to using a phosphate eliminator? How does it differ from algaecides? 

F. T., Coral Springs, FL, 8/20/2012

Phosphate Eliminators are typically used in conjunction with algaecide and standard swimming pool maintenance. When added to a swimming pool, these compounds react with the phosphates and drop their concentration from parts per million to parts per billion. Phosphates are a vital nutrient for all types of algae and their almost total removal from the water interferes with the ability of algae to grow and thrive. Literally, the algae starves to death! No algae - no problems with green water. All this sounds great, but as long as you have people in swimming pools, there will be phosphates added in some quantity. For this reason the phosphate eliminator has to be added on a periodic basis.  A new and better way to remove phosphates and heavy metals, at the same time, is with the POOL REFRESH system. Just add the combination, of two products, to the pool and let the pool filter and/or vacuum get rid of the problem. A phosphate test can be performed occasionally to determine the need to add additional product. As additional assurance against algae growth, it is a good idea to maintain the normal additions of algaecide. The product is a worthwhile addition to the anti-algae arsenal. The only downside is that its initial addition will result in a precipitate that has to be removed by filtration and/or vacuuming. Subsequent product additions are much less of a problem because of the reduced phosphate content of the water. I hope that I have satisfactorily explained the product. Enjoy the summer.

Sincerely. Alan Schuster, 8/20/2012


► High Phosphate Level?

I have looked through your website and have found very interesting information. However, I have not found anything that specifically addresses my question. We are located in Virginia Beach, VA and have had our pool for 4 years (35,000 inground). Last year, we were having a nightmare trying to deal with algae even though all the chemicals seemed to be properly balanced. It turned out to be a high level of phosphates. So we treated for the phosphates with 1 treatment (our initial level had been close to 10,000 PPB). Everything seemed to be fine after that and we enjoyed the rest of our summer in the pool.  During the winter, we converted from a chlorinator to a salt generator. Also during this time, a road was put through very close to our house, kicking up dirt and dust (our development is situated on land that was farmed until about 25 years ago). Opening our pool in the spring was awful, but after a couple of weeks, everything seemed to be going well. We used 2 phosphate treatments during the opening. We have since used about 5 treatments and are again having trouble keeping our chlorine levels up. At last check, we were close to 10,000 PPB again. Construction has been completed for months on the road, we've been in a drought situation this summer and the bather load has not been high. I am just at a loss as to what could be boosting the levels so quickly. We have had to add some water this year (we are on city water). So these are my questions - is there any way to remove the phosphates without having to constantly vacuum to waste after treatment? I had read some of the posts where they allowed it to go through the filter, then backwashed (we have a DE filter). Does this require a specific type of phosphate remover? We haven't been able to treat for the last month because the heat and no water movement would cause more trouble than it would be worth. By the way, the water is still clear, but we have had to add shock every week to keep the chlorine levels up. Constant removal of the water through vacuuming to waste has become cost prohibitive. In the spring, my water bill soared to over $200 and was close to that in the middle of the summer - that doesn't include the $90 waste water bill that comes along with it.  Is there a product that you can recommend as part of regular maintenance to keep the phosphates down? Thanks for your help and all the info.

Tracey., Virginia Beach, VA, 8/24/2017

If you add the phosphate remover, to the skimmer, it might clog your DE filter or boost the pressure too high. If not, it should reduce the need to vacuum to waste. You won't know until you try it. Other types of filter are less prone to clogging. Add in 1/4 increments and watch the pressure: stop if it is too high.   POOL REFRESH will remove phosphates and, at the same time, it can remove potentially, stain-causing iron and copper. It sounds like your salt chlorine generator is not producing enough chlorine or the chemistry is not right. Check the salt level and make sure it is within the desired range. Make sure that the pH is 7.2-7.8, as high pH will make chlorine less effective. Make sure that the water circulation is good. More circulation creates dead zones that promote algae growth. The Circulator is the affordable, simple and effective way to better circulation. Make sure that the salt cell is clean, the unit is operating properly, the water flow is strong, the salt level is right and that it is being operated for enough hours per day. More hours and or a higher setting = more chlorine produced. I hope that this information will prove helpful.

Sincerely. Alan Schuster, 8/25/2017

► Phosphate Swimming Pool Woes?

We are opening our under-ground pool on May 3rd. Last year I dealt with a phosphate problem all summer long. Levels would be 500ppb. I don’t remember how many times I put in phosphate remover. Would get the level down, then it would be back up again.  My pool company just keeps selling me phosphate remover, and saying to shock it.  My kid’s college fund went into it. I was at the point of cementing it in, would make a great basketball court. We have owned the pool for seven years and my in-laws had it 9 years before us. We have never had a problem with high phosphate levels before. What has changed in the past three years surrounding our yard. Dig pond west of pool about 100 feet, potato fields three miles to the west (plane spray fields) and new city water treatment plant 3 blocks to the north (which the newspaper reported last fall that it has high phosphate). We have a sand filter, use trichlor in a chlorinator, and shock. Any suggestion would be welcomed. Would it be wise to totally drain the pool and start fresh. Vinyl pool liner, and 20,000 gallon. Live in central Minnesota. Please help!

Kathy, 4/18/2015

There were pools before there were phosphate removers. Removing phosphates is a good thing, as it deprives algae of a vital nutrient. People and their wastes are a source of phosphates and as long as the pool is used, there will be some present. 500 PPM: that's parts per billion. Not exactly a high level. Draining the pool is a poor option. The tap water can contain phosphates and fertilizers certainly contain them. There was not one word in your letter about algae. That being the case, I suggest that you add a phosphate remover, such as POOL REFRESH, at the start of the season and continue with good maintenance practices. At signs of a loss of water quality, shock the pool and have the phosphates tested. If you maintain good sanitizer levels, there should be few problems. Good luck and enjoy the season.

Sincerely. Alan Schuster, 4/19/2015


► White Sediment?

I added phosphate eliminator, as suggested, on Friday night along with the liquid chlorine. The pool water quickly went cloudy and then we left for the weekend. We did not return until late last night, so when I checked the pool this morning the water looked very clear. But there were areas on the bottom that had "milky" colored deposits on the bottom. The deposits almost seemed cloud like. I added the "sparkling clear" and left the pump running. I will get my wife to turn off the pump this morning and then get to the vacuuming later today. Does all this sound about right? We had some fairly heavy rain a couple of weeks ago and that is when most of this started. I have considered the passing issue in the sand filter. This is only our 3rd season with the new pool and I thought that I would change over the filter media when we close the pool this fall. When we backwash the pool do we tend to break up the channels that may develop in the sand?

Mark H., 7/10/2006

The phosphate eliminator caused the phosphates to precipitate out. The filter may not have gotten it all. Evidently, the white sediment is precipitated phosphates and needs to be vacuumed up. Sand should be changed every few years. Even better than sand would be a zeolite sand filter replacement media. It will clearly make an improvement in the water quality. I hope that I have been helpful.

Sincerely. Alan Schuster, 7/10/2006


► Mustard Algae Blues?

I discovered your website last evening and you have an array of information. Thanks for helping to educate us. My situation is as follows: we had an in-ground pool built last February. The pool was installed with a salt chlorine generator and an automatic pool vacuum to make life easier for my husband and I. Since the completion of the pool, we have had a problem maintaining adequate chlorine levels. It comes in spurts. We are aware that after rain, we may have lower chlorine levels, but the inadequate levels are also there when there hasn't been a lot of rain.  The other chemicals (pH, calcium, stabilizer, salt, etc.) are being maintained correctly. My husband checks the water weekly and brushes the pool and cleans the filter weekly. My husband has tried the approach of cleaning the generator's cell, but the pool still doesn't maintain adequate levels of chlorine. We are usually putting in chlorine on a bi-monthly basis. We even had a rep for the generator company come out and he informed us our chlorine generator is producing chlorine. The generator has consistently been on 100% boost. Due to the chlorine problem, we are continually battling an yellow-orange powdery residue on the walls and stairs of our pool.  I believe it is mustard algae from lack of chlorine (when the readings are low). I also notice the stairs and bottom of pool feel slippery. When the generator company rep came out, he informed us we have a high level of phosphates in our pool. We weren't aware we were to check for phosphates. The pool store that checks our water does not check for phosphates either.  We later found out the store will check for phosphates if requested. Anyway, the rep told us to use the POOL REFRESH phosphate treatment program he provided and this should correct our problem with phosphates, chlorine and mustard algae and then our pool should maintain adequate levels of chlorine that are produced by the generator. We treated with the phosphate treatment and after re-testing, we still had a high level of phosphates. We did a second treatment and just re-tested yesterday and the phosphate level is still at 500 ppb. I am losing hope with pool maintenance. We got the salt generator so we wouldn't have to continually have to add chlorine, but we still have to add chlorine. We treated for phosphates, but it isn't going away. Our pool has mustard algae. The bottom is slimy. Any suggestions?

Sharon G., 6/18/2006

The fact that you have mustard algae and slime on the walls, implies that the demand for chlorine is very high. Under these circumstances, it appears that your salt chlorine generator is not able to produce enough chlorine to maintain a proper Free Chlorine level. It is a matter of playing catch up. The phosphates are not helping the situation either: they act as a fertilizer and promote algae growth. Adding POOL REFRESH phosphate eliminator was a good thought. However, 500 PPB may still be too much. To be effective you must lower the level closer to zero. Once you level the playing field and get rid of this backlog of algae and slime, it should be easier for the salt chlorine generator to keep up with the chlorine requirements of the pool. Step one should be to treat again for phosphates. Step two, should be to add sufficient chlorine to boost the Free Chlorine level to 5-10 PPM and keep it there long enough to destroy the algae and slime.  It may take a lot of chlorine to do this and the longer it drags out the more chlorine will be required. As long as it is not dead, it will continue to grow.  Step three should be to add a treatment for mustard algae. You can use either a copper algaecide or a sodium bromide product. Both seem effective. Check with the salt chlorine generator dealer, as to their preferences for a mustard algae treatment. I hope that this information will prove helpful. Good luck.

Sincerely. Alan Schuster, 6/18/2006


► Effects Of Winter On Phosphate Level?

I have very high phosphates in my pool around 2500. Will they go down in the winter or will they stay the same?

Edith B., 11/13/2007

Winter will have little or major effect on the phosphate content. In the spring, adding fresh water could lower the level, depending upon the phosphate content of the replacement water. If vegetation and debris was in the pool, over the winter, the decaying matter could add to the phosphate content. High phosphate levels make algae growth more likely and poor pool water chemistry less forgiving. You need to add a phosphate remover, such as POOL REFRESH and get the level down to a few hundred PPB. Otherwise, you will be forced to maintain a higher free chlorine level and be more disciplined about maintain a free chlorine level. I hope that this information is helpful.

Sincerely. Alan Schuster, 11/1/3/2007


► Unexpected Rise In Phosphates?

Last week I had a phosphate level of well under 100ppb. I have been using Phosphate Reducer all winter. This week the phosphate level has suddenly jumped up to 900 ppb. I've added a couple of inches of water to the pool and we had a night of rain. All other chemistry in the pool is good. Am I throwing money down the drain by adding more Phosphate Reducer? I had a couple of incidents last year with my pool tuning cloudy, but generally the pool is OK. And for the most parts crystal clear. I did have a Mineral Sanitizer, but was planning on dropping it this year. What would you advise? Regards.

Max S., High Point, NC, 4/4/2009

I would not refer to it as "throwing money down the drain." Water that is low in phosphates is less likely to support algae growth and that is a positive! Using POOL REFRESH will remove phosphate, as well as a host of other problematic heavy metals and minerals. You need to put things in perspective: 900 PPB or 0.9 PPM is a trace amount. It is lawn fertilizing time and the recent rains could have introduced some runoff into the pool.  I hope that this information is helpful.

Sincerely. Alan Schuster, 4/4/2009

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