Phosphates

Homebrewale

Silver Supporter
Apr 21, 2020
1,208
Holly Springs, NC
Pool Size
22000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair iChlor 30
I know the popular opinion around here is that phosphates are not a problem if the water is properly balanced. But that is the key words - properly balanced. If the pool for some reason becomes out of balance, you can get algae because food (phosphate) is available. I've only had an issue one time with algae which happened from unfortunate timing. It was probably about 8 years ago. I decided to pressure wash my concrete deck and used a concrete cleaner that had phosphates. I sent the levels high in my pool from overspray. Then I left for a week vacation and let my neighbors use the pool. The chlorine levels got out of whack and I got an algae bloom. I learned two things. One is never use a phosphate cleaner around a pool. Another is to not let the levels of phosphate get too high because there are a lot of things that can get a pool out of balance. The common one for my pool is summer torrential rains that will sometimes almost overflow my pool.
 
So your chlorine got out of whack and you got algae. And phosphates are to blame? Phosphates that you never bothered to test but "know" they were high because you were cleaning your concrete?

Yeah... Gonna go ahead and call that a pretty weak argument.

BTW, welcome to TFP.
 
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I know the popular opinion around here is that phosphates are not a problem if the water is properly balanced. But that is the key words - properly balanced. If the pool for some reason becomes out of balance, you can get algae because food (phosphate) is available. I've only had an issue one time with algae which happened from unfortunate timing. It was probably about 8 years ago. I decided to pressure wash my concrete deck and used a concrete cleaner that had phosphates. I sent the levels high in my pool from overspray. Then I left for a week vacation and let my neighbors use the pool. The chlorine levels got out of whack and I got an algae bloom. I learned two things. One is never use a phosphate cleaner around a pool. Another is to not let the levels of phosphate get too high because there are a lot of things that can get a pool out of balance. The common one for my pool is summer torrential rains that will sometimes almost overflow my pool.
Balance really has nothing to do with it. When we talk about "balance" we are generally talking about a pool with pH, Alkalinity and Hardness within acceptable ranges.

You pool got algae for one reason, insufficient chlorine. We maintain our pools with chlorine sufficient to keep algae from growing. As the level of CYA/Stabilizer in the water inhibits the chlorine from doing it's job, we always keep the chlorine in proper ratio to CYA.

 
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Balance really has nothing to do with it. When we talk about "balance" we are generally talking about a pool with pH, Alkalinity and Hardness within acceptable ranges.

You pool got algae for one reason, insufficient chlorine. We maintain our pools with chlorine sufficient to keep algae from growing. As the level of CYA/Stabilizer in the water inhibits the chlorine from doing it's job, we always keep the chlorine in proper ratio to CYA.


I may use the term "balance" more loosely than you but to me that means everything is at the proper level including chlorine. Yes, the chlorine got low while I was away because of the heavy use by the neighbors. Chlorine can also get low when the pool is heavily diluted which can occur when I get a 3-4" rain that does happen during the summer. I have to do a number of adjustments after one of those rains. Sometimes my salt level will drop 300ppm.

Like you said, you keep your pools at sufficient chlorine level but sometimes levels can get out of balance. Otherwise, you wouldn't need to test and adjust. If those levels get out of whack while on a two week cruise, you come home to a pool with algae. Without phosphates, that is less likely to happen.
 
So your chlorine got out of whack and you got algae. And phosphates are to blame? Phosphates that you never bothered to test but "know" they were high because you were cleaning your concrete?

Yeah... Gonna go ahead and call that a pretty weak argument.

BTW, welcome to TFP.

I know they were high because I do test. I don't know how you got from my post that I never bother to test. Thanks for putting words in my mouth.
 
I put words where none are. You didn't provide a number, so one could only conclude one didn't exist. Especially since "high" is an completely nebulous and irrelevant statement. What pool stores consider high is based on their desire to sell phosphate removers, what we consider high is based on levels that actually may cause issues.

Frankly though, none of that changes any part of what myself or Tim said. Your chlorine level went out of whack and you got algae. There is no basis to blame this on phosphates, it almost certainly would have happened regardless of that level.
 
I put words where none are. You didn't provide a number, so one could only conclude one didn't exist. Especially since "high" is an completely nebulous and irrelevant statement. What pool stores consider high is based on their desire to sell phosphate removers, what we consider high is based on levels that actually may cause issues.

Frankly though, none of that changes any part of what myself or Tim said. Your chlorine level went out of whack and you got algae. There is no basis to blame this on phosphates, it almost certainly would have happened regardless of that level.

It was termed high because the test will only read up to 1000 ppb. It took 3 bottles of phosphate remover to get the level below 1000 ppb. There is a basis for blaming the phosphates because in the 14 years I've had my pool, it was the only time I have had algae. I have never had one opening with green water which is the likely time it will occur after sitting all winter without chlorine additions. It was this one time where I got too much phosphates into the pool.

I'm also pretty good with chemistry since I'm a chemical engineer. As you have stated more than once, you won't get algae if you have proper chlorine levels. Congratulations for your pool never having improper chlorine levels, even at opening. I can't match your perfection. Mine will go too high or too low and I make adjustments to the proper levels.
 
David Carr,

you took Donldson's post out of context. Reviewing the entire thread, his post was to the point and appropriate.

Our method of pool care is based on provable science developed for over 15 years and we somewhat dismissive about anecdotal reports (from a 10-day member) that we know to be incorrect.

With only one post, I hope you stick around and learn how serious this forum is..........it's eye-opening if you decide to give it a try.

I assume that 10 day member was directed at me. I was not arguing your provable science. I was arguing the times when your provable science doesn't apply. I'm an engineer so I like logic problems.

Let's fill up 4 different plastic water containers and sit them on your pool deck. The first has zero phosphates, the second has 500 ppm phosphates, the third has 1000 ppm phosphates, and the fourth has 2000 ppm phosphates. Now for several weeks, test everyday and maintain the proper FC/CYA. I agree with all of you that says phosphates are not a problem. No algae will form. For some reason, you thought I was arguing against that.

Now take 4 more different plastic water containers with the same phosphate concentrations as the first experiment. Establish the proper FC/CYA. Now don't add any chlorine to maintain proper FC. FC falls as the containers sit in the hot sun to practically nothing. Let it sit there for several weeks like the first test. Will algae grow in the water? Will it grow to the same levels in each container or will the container with the highest phosphate concentration have the most algae? This experiment represents the pool pump dying or the SWG failing while you are away on a long vacation. So that's why I say phosphates matter. It doesn't matter in a functioning pool with proper testing and maintenance but it does matter if something bad happens and you are not around. I have found the broken equipment issue seems to happen when you are not home.
 

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Contrary to what many believe, TFP does not exist to discuss ALL methods of pool care, but a singular method that has come to be known as Trouble Free Pool care. It involves accurate self testing of your pool water and only adding what the pool needs.

We want pool owners to understand that "traditional" methods of pool care as taught by many pool stores are often adding things to your pool that you really don't need. From CYA in stabilized pool products to the UV and ozone in the "lower chlorine" methods we feel you don't want or need them.

If you want to use phosphate remover, by all means do. But, it's not part of the methods we teach.
 
If a pool pump dies, and thats something we do hear here routinely we just advise folks to maintain their FC with liquid chlorine and either mix it around manually with a broom or using their robots or a sump pump. May lose water's shine because of loss of filtering but shouldn't get algae.

If you truly want to use it at least get the good stuff and not the weak junk Leslie's sells -PhosFree, ugh. Orienda would be a better product.

maddie
 
Contrary to what many believe, TFP does not exist to discuss ALL methods of pool care, but a singular method that has come to be known as Trouble Free Pool care. It involves accurate self testing of your pool water and only adding what the pool needs.

We want pool owners to understand that "traditional" methods of pool care as taught by many pool stores are often adding things to your pool that you really don't need. From CYA in stabilized pool products to the UV and ozone in the "lower chlorine" methods we feel you don't want or need them.

If you want to use phosphate remover, by all means do. But, it's not part of the methods we teach.

Getting a very high level of phosphates into a pool from a concrete cleaner is not a typical occurrence so traditional methods do not apply. That is what happened in my pool. I don't typically use phosphate removers but the levels in the pool were off the charts.
 
I had a very similar experience with phosphates. You can definitely operate a pool without dealing with phosphates but under certain circumstances, removing them can make you life a little bit easier. When it comes to pool maintenance, I admit that I am lazy and don't really want to "watch" my levels every day. Every other week is more my speed so I need a bit of insurance. Removing phosphates has given me that extra insurance. Plus it has also allowed me to run my SWG at a lower % (i.e. lower FC target) than I had before without any ill effects which saves me money long term (i.e. SWG replacement costs). Anyway don't think that every one on this forum is opposed to phosphate removers:

 
If you want to use phosphate remover, by all means do. But, it's not part of the methods we teach.
I think that quote from Tim5055 above states TFP's position pretty accurately. Any member on this forum can use ANY method of pool care that they want.

However, TFP does not exist to discuss and debate every method and technique of pool care, but rather to teach a method that we have collectively proven to be extremely effective. That method does not include the use of phosphate remover.

I would also add that testing every couple of weeks can sometimes be successful for VERY EXPERIENCED pool owners, TFP believes strongly that folks should maintain a more frequent testing regimen........mandatory almost for newbies and "good practice" for all of us would be once weekly or so for ALL the tests and daily for chlorine and pH.
 
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I think that quote from Tim5055 above states TFP's position pretty accurately. Any member on this forum can use ANY method of pool care that they want.

However, TFP does not exist to discuss and debate every method and technique of pool care, but rather to teach a method that we have collectively proven to be extremely effective. That method does not include the use of phosphate remover.

I would also add that testing every couple of weeks can sometimes be successful for VERY EXPERIENCED pool owners, TFP believes strongly that folks should maintain a more frequent testing regimen........mandatory almost for newbies and "good practice" for all of us would be once weekly or so for ALL the tests and daily for chlorine and pH.

If it doesn't rain for a week or two which is common around here, why would you need to test salt or CYA. Neither are consumed while a pool is running. They only change due to dilution.
 
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If it doesn't rain for a week or two which is common around here, why would you need to test salt or CYA. Neither are consumed why a pool is running. They only change due to dilution
Once more, ANY member here is welcome to manage their pool any way they would like. TFP suggests guidelines that we know to be effective and practical.

TFP believes it is important to stay tuned in to your pool. People that start as newbies usually test most every day. Those same newbies after 2-3 years can literally walk by their pools and see what it needs. That's because they tested frequently when they were starting and learned from experience what their pool needed.

Actually, you test CYA and salt hoping they DON'T vary......that's how you learn to read your pool.....you are looking for consistency. So you test to make sure you don't have a run away autofill (for example) that is steadily diluting your salt and CYA and, although you don't know, it is eye-popping your water bill because you don't test very often.

So, please test as often as YOU feel necessary and no more than that. But please don't ask TFP to approve.
 
I don't have any autofill on my pool. It only gets filled two ways - rain or manually sticking hose in pool. Yes, I will operate my pool as I see fit. As an engineer, I generally like a scientific reason why something is done instead of this is the way we do it. For my pool, there is no reason based on science to test salt or CYA on a weekly basis if it has not rained or I have not tossed a hose in the pool. With 16 years of operating experience, I'm not a newbie.
 
One thing to be aware of is that CYA does degrade over time for reasons besides splash out and leaks:

 
We don't write these guidelines for someone with 16 years experience and an engineer to boot. We write them for newbies who want to learn best practices on how to care for their pool. You already know all those so I can't quite figure out why you ask our advice?

I have to remind folks all the time we are a teaching forum and we teach what we know works.
 
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