Phosphates can be a serious problem

[jaybo500]

Split off of No Chlorine / Phosphates. JasonLion

I just saw your post, so by now you have probably solved the problem. However, if not let me say that phosphates can be a serious problem. A lot of these pool mavens dismiss it as as a non-issue, but depending on your region they can indeed be an issue. I am in southwest Florida, home of the phosphate mining capital and I regularly deal with them in the 80 pools that I service. Believe me that when you cannot keep chlorine in the pool and you have sufficient CYA, phosphates can be the problem. Dose the pool with a quart of remover (minimum), not 3 or 6 ounces, run filter 24 hours, clean the filter numerous times, and recheck level. Then dose pool with a remover of 3 ounzes every month to eliminate any growth.

 

[JasonLion]

I am curious how you can explain my pool. My phosphate level varies somewhat, but is typically around 4,000, and I have yet to have any problems at all because of it. My chlorine demand is well below the average for most pools here, less than 1 ppm per day, the water is as clear as glass, and everything just works perfectly with minimal attention.

Removing phosphates will often (not always) stop you from getting algae. But that only covers up some other problem. If the pool is properly sanitized, you won't get algae, with or without phosphates. If the pool is not properly sanitized, algae is only one of the problems you might have. Keeping algae away don't insure that your water is safe from viruses and bacteria.

 

[chem geek]

My pool has 2000-3000 ppb phosphates. I will say that having phosphates and nitrates, which are algae nutrients, can make a pool more reactive in that algae can grow quickly if the chlorine level relative to CYA gets too low or to zero, but algae with even ideal nutrient levels is limited in its growth rate by temperature and sunlight and can only double in population in such ideal conditions every 3-8 hours depending on species.

There is no question that if you don't maintain a minimum FC of at least 7.5% of the CYA level in a manually dosed pool that the algae can grow faster than chlorine can kill it, leading to the kind of mysterious chlorine demand you allude to. Nascent algae growth is not visible but still consumes chlorine. Eventually the water will turn dull and then cloudy and then green (the specific sequence depending on the type of algae), but all of this can be prevented by simply maintaining an appropriate FC/CYA ratio since the chlorine alone can kill the algae faster than it can grow.

We've also seen pools that have used phosphate removers yet still got algae, though that is more rare. This could be because the phosphate removers only remove one form of phosphate, orthophosphate (i.e. inorganic phosphate) and not small organic phosphates that algae can still use though more slowly.

So phosphate removers can be seen in the same vein as algicides. They can work to inhibit algae growth, but they are not necessary if proper chlorine levels are maintained appropriate to the CYA level. If you have kept a log of the FC and CYA levels that were typically in the pools that had unusual chlorine demand or algae growth, then that would be helpful to know. Even the "standard" recommendation of many SWG manufacturers of 1-3 ppm FC with 60-80 ppm CYA is not sufficient to prevent algae growth -- 80 ppm CYA should have around 4 ppm FC minimum (the minimum FC for SWG pools is somewhat lower than for manually dosed pools).

Richard

 

[teapot]

Good morning all,

I am also curious Jason, you post very good figures for chlorine loss (1ppm) and as you say phosphates at 4000ppm.

Without any doubt if there is enough free chlorine then the pool stays problem free hence your BBB system.

I wonder how much chlorine your system is generating throughout the day, if for example it produced 5ppm yet overnight it shows only 1ppm drop then you are actually using 4ppm/day although you are showing a drop of only 1ppm.

If the water has most of its phosphates removed then the swg may only produce 3ppm and yet you may still only drop 1ppm overnight so you are actually using 2ppm/day

Does that matter? not if everything is ok surely. There is a post on TFP http://www.troublefreepool.com/ph-201-t16781.html?hilit=rain water
Showing that the rain water is acidic, by products of industry and pools are believed to be adding to the acid rain issue which is harming the environmemt so reducing chemical levels should be the aim of everyone.

If you remove one of the main areas that uses chlorine (algae) by reducing it's food supply, then chlorine usage will reduce yet you will still have a properly sanitised pool.

 

[The Mermaid Queen]

**caution: the mermaid has yet again wandered into the deep end...

If you remove one of the main areas that uses chlorine (algae) by reducing it's food supply, then chlorine usage will reduce yet you will still have a properly sanitised pool.

But again, if you are diligent to keep the FC levels above the minimum for your CYA, you won't get algae growth in the first place: if there is no algae present to eat the food (phosphates and nitrates) and the food itself does not utilize chlorine, then it is a moot point.

 

[Bama Rambler]

**caution: the mermaid has yet again wandered into the deep end...

But again, if you are diligent to keep the FC levels above the minimum for your CYA, you won't get algae growth in the first place: if there is no algae present to eat the food (phosphates and nitrates) and the food itself does not utilize chlorine, then it is a moot point.

Not wandered, but dove right in! Excellent post. It doesn't matter how much food you have if there's nothing to eat it.

 

[spishex]

Without any doubt if there is enough free chlorine then the pool stays problem free hence your BBB system.

I wonder how much chlorine your system is generating throughout the day, if for example it produced 5ppm yet overnight it shows only 1ppm drop then you are actually using 4ppm/day although you are showing a drop of only 1ppm.

If the water has most of its phosphates removed then the swg may only produce 3ppm and yet you may still only drop 1ppm overnight so you are actually using 2ppm/day

Does that matter? not if everything is ok surely. There is a post on TFP http://www.troublefreepool.com/ph-201-t16781.html?hilit=rain water
Showing that the rain water is acidic, by products of industry and pools are believed to be adding to the acid rain issue which is harming the environmemt so reducing chemical levels should be the aim of everyone.

If you remove one of the main areas that uses chlorine (algae) by reducing it's food supply, then chlorine usage will reduce yet you will still have a properly sanitised pool.

You're assuming that the presence of phosphates means there is algae present, which isn't the case. If the pool is clear and holding FC at normal levels (~10% of CYA) then there isn't any algae there to begin with, and what does get introduced is dead in 30 seconds whether it has food or not.

You posted this in another thread:

Just think about it, if you are having a pool party and you don't provide any food how long will your guests stick around?

Our argument would be that if you kill all your guests before you put the food out then none of it gets eaten.

 

[lovingHDTV]

I am curious how you can explain my pool. My phosphate level varies somewhat, but is typically around 4,000, and I have yet to have any problems at all because of it. My chlorine demand is well below the average for most pools here, less than 1 ppm per day, the water is as clear as glass, and everything just works perfectly with minimal attention.

Removing phosphates will often (not always) stop you from getting algae. But that only covers up some other problem. If the pool is properly sanitized, you won't get algae, with or without phosphates. If the pool is not properly sanitized, algae is only one of the problems you might have. Keeping algae away don't insure that your water is safe from viruses and bacteria.

Sounds like Jason needs to quit being so good with the chlorine and allow an algae outbreak to eat up all that yummy algae food. Then your phosphate levels will come down.

I also suggest adding a little ammonia, as ammonia is algae caffeine!



dave

 

[spishex]

Believe me that when you cannot keep chlorine in the pool and you have sufficient CYA, phosphates can be the problem. Dose the pool with a quart of remover (minimum), not 3 or 6 ounces, run filter 24 hours, clean the filter numerous times, and recheck level. Then dose pool with a remover of 3 ounzes every month to eliminate any growth.

No, phosphates can't be the problem. They do not increase chlorine demand in and of themselves. Algae could be the problem, and yes algae need phosphorus to live, but they also need other nutrients (nitrogen, carbon, etc.), along with light and water. Perhaps if we added some water remover to the pool the problem would go away?

We can only test for and remove one form of phosphorus in the water (orthophosphate). More complex species exist in the water and even more phosphorus is probably being added to the water regularly since it was there to begin with. You'll never get it all out, no matter how compulsively you scrub. You'll just drain your wallet.

Algae can also store phosphates in their bodies, allowing them to live and grow in a zero-phosphate environment for weeks, so the notion that phosphate removers work on existing outbreaks by starving them is bogus.

There are thousands of hot tubs running today with some form of pH stabilizing product in the water. What's the main ingredient? Phosphorus. Enormous amounts of it. Yet they're algae free. Usually because there's no light (the biggest limiting factor in algae growth) hitting the water 99% of the time. So if you really want to deprive algae why not get your customers to pony up the dough up front for an automatic cover instead? Not only will it keep algae down, it will stop all kinds of organic material from entering the pool and prevent evaporation and chlorine degradation from UV light.

:blah:

 

[anonapersona]

Do I recall that dead leaves are a source of phosphates??

 

[spishex]

Do I recall that dead leaves are a source of phosphates??

Yup, and living ones. Other sources:

- Fertilizer
- Urine (Fun fact: A normal adult excretes 1.3 - 1.5 g of phosphorus per day.)
- Most soaps, shampoos and detergents
- Processed foods and drinks
- Water Runoff
- Deodorants/Antiperpirants
- Bird Droppings (and feces in general)

But the biggest culprit is "Stain and Scale" products which are similar to the pH stabilizers I mentioned earlier. Ironically one unnecessary product begets another. Here's a cool write up on what sources add how much.

 

[mas985]

While I think that the experience of pool owners is very important, I think we need to be careful about extrapolating these experiences to ALL pools. It seems to me that there are way too many variables involved to do that effectively and there is a chance that it might not be the correct advice. So reviewing some of the comments that I have read on the forum:

A pool can be properly maintained with high phosphates. This has been proven true via the experience of some pool owners. However this only proves the case for those pool owners and may or may not apply to ALL pools.

There are over 7000 species of algae and like other plant life on earth are distributed throughout the world. Maintaining a pool with high phosphates may not be an issue in many parts of the country/world but could possibly be a problem in another because they are dealing with a different species.

Phosphate removers will only remove one type of phosphate. Some in the industry claim that phosphate removers have cleaned up pools they maintain. This could be due to the algae surviving on the one phosphate which the removers are removing so this could be true as well. But then again, they may not make a difference either but the important thing to remember is that they may work is some cases.

What I find very unfortunate is that I will sometimes read a post which will claim that phosphates are “never a problem” or should “always be ignored”. Given all of the variables involved and the varying experiences involved, I do not see how that could possibly be true.

High phosphates will likely always play a role in pool chemistry. The real question is how much of a role. So telling a pool owner that they do not matter is simply not true. They may be able to properly maintain a pool with them but they will still play a role even if it is very small.

Most pool owners are not perfect and unless they have an automated chlorinator, sometimes the chlorine level will dip below the recommended levels. A pool with high phosphates will likely develop algae sooner than one with lower/no phosphates and require more chlorine to remove it.

We know that some algae take much more chlorine and time to kill it than others (e.g. mustard algae). It stands to reason that if there is a food source in the water, the algae will grow faster and perhaps require more chlorine to kill it and give the pool owner less time to do so.

So while it may be possible to maintain a pool with high phosphates, it may not be an ideal situation either. Phosphate removers may not be the solution but nothing that I have read on this forum would indicate that they never work either. It would seem to me that there are some conditions where they may work so it still should be an option to the pool owner if they want to try it. However, they should also know that it there is a good chance that it may not help at all.

As Albert Einstein once said:

“Whoever undertakes to set himself up as a judge of Truth and Knowledge is shipwrecked by the laughter of the gods.”

 

[spishex]

Phosphate removers may not be the solution but nothing that I have read on this forum would indicate that they never work either. It would seem to me that there are some conditions where they may work so it still should be an option to the pool owner if they want to try it. However, they should also know that it there is a good chance that it may not help at all.

Fair enough, Mark. Perhaps I should say "usually unnecessary" instead of "useless". But I think you could make the same argument for any product on the shelf. At what point does this narrow window of conditions just serve to prove the rule? Even if we concede that they can be helpful in a few instances, we still have the problem of them being over-prescribed. In my area it's to the point that some service techs are adding p-remover without even testing phosphate levels to begin with, so the whole thing gets me riled up.

 

[spishex]

Wait. What? How did you go from asking questions like this...:

Can someone please define what "vac to waste" consists of. Is it simply backwashing or cleaning your filter?

( here )

And this:

Pool store guy said if your pH and Alkalinity are both high you would use muriatic to bring them down. If only pH is high you use sulfuric, as it has little impact on Alkalinity. Any thoughts?

( here )

...to being an expert on Phosphates with 80 pools under your belt in just 6 days? :|

Not to get all ad hominem on you but something doesn't fit.

 

[chem geek]

Mark,

That was an excellent post and delineates my feelings about this as well. Many chemical treatments are effective at preventing or inhibiting algae growth, but they also have various pros/cons and none is perfect (i.e. works completely, is free or a one-time dose, has no side effects of any kind). Since one needs chlorine for disinfection anyway, maintaining an appropriate FC/CYA ratio to prevent algae growth seems the most practical, but it's really a personal choice (and some heartier algae, such as yellow/mustard, give more challenges).

spishex,

Regarding that link on phosphates, my municipal water district in Marin County just north of San Francisco adds 300-500 ppb phosphates as a corrosion inhibitor to the water so this isn't just done in the places listed. As for stain and scale products, the more effective ones have HEDP which is an organic phosphate and this chemical is more resistant to breakdown from chlorine so lasts longer. The less effective ones often have EDTA which does not have phosphate and this chemical breaks down more quickly from chlorine to the point where one can notice an increased chlorine demand when using larger amounts of this product. So using the more effective metal sequestrant adds a source of phosphates to the pool water.

For my own pool, I'm not really certain where the higher phosphate comes from. For sure, the fill water was a starting point, but with use of a pool cover I don't get a lot of evaporation and refill. I may do some jar tests with some fertilized soil in our garden to see the phosphate level as I suspect that fertilizer laid on top of the soil is far more concentrated and could get blown into the pool, but I agree that it just doesn't seem like the amounts would be very high. In the earlier days of my pool use I may have added a metal sequestrant as a preventative, but I don't think it was HEDP but I don't remember.

Richard

 

[duraleigh]

What I find very unfortunate is that I will sometimes read a post which will claim that phosphates are “never a problem” or should “always be ignored”. Given all of the variables involved and the varying experiences involved, I do not see how that could possibly be true.

Certainly, that thinking is correct but it doesn't address the question of how many pools will, in fact, not respond to the methods we teach.

One of the guiding principles I think we should maintain on the forum is that we have to teach generalities. If what we teach is over 99% correct (and I think it is), that's good enough.

My reasoning is if you teach all the "yes, but in some rare circumstance" variations, the average person on this forum will frequently misinterpret something that's only partially true or that sidetracks him from what he should be learning.

I see newbs here that have read posts on borates and think they have found the "magic bullet". I see newbs all the time purchasing phosphate remover and not understanding why the algae doesn't go away even though there FC is 0.

For newbies to focus and learn, we need to teach simplicity. Simplicity always involoves chlorine.

I believe we muddy up the waters when we include phosphates as a realistic cause of poor water quality.

 

[JasonLion]

I wonder how much chlorine your system is generating throughout the day, if for example it produced 5ppm yet overnight it shows only 1ppm drop then you are actually using 4ppm/day although you are showing a drop of only 1ppm.

Total chlorine added to the pool over 24 hours is less than 1 ppm. Depending on the weather it is sometimes much less. This is with one person swimming for less than 30 minutes per day and many large trees providing lots of shade. Usage is higher when we have a pool party.

Some in the industry claim that phosphate removers have cleaned up pools they maintain.

There is no question that removing phosphates will often prevent algae. That doesn't mean that removing phosphates is something that is worth doing. There are other ways of preventing algae.

Phosphate removers suffer from a number of defects and some seriously misleading marketing tactics. Under ideal conditions, removing phosphates can reduce your chlorine consumption a little and reduce the odds that you will get algae when you ignore the pool (allowing the FC level to fall to zero for a time). However, for most people most of the time, there are other approaches to achieve the same results that are significantly easier and less expensive.

The worst problem with phosphate removers is that they completely fail the "trouble free" test. For a significant percentage of users, phosphate removers cause more problems than they prevent. Anyone with significant phosphate levels in their fill water will have to spend large amounts of money on phosphate removers, then spend days, or weeks, suffering through cloudy water, only to have the phosphate level jump up again the moment they have to add more water to top off the pool. In my area, the tap water phosphate level is over 1,000. Under those conditions, getting all the phosphates out after spring opening is a large, expensive, time consuming, and frustrating project.

Removing phosphates is never required. 100% of the time it is possible to maintain an algae free pool with chlorine alone. I am not saying that chlorine alone is the ideal approach for everyone, but chlorine alone always works. Some people may need to use a higher FC level than others who are nominally in the same situation, but there is always an FC level such that you will be algae free. Swimming pools have been around for much longer than phosphate remover has been around. Before phosphate remover existed, people still had algae free pools.

Another problem with phosphate removers is the high pressure sales tactics used by some pool stores. Many pool stores insist that anyone with phosphate levels above 100 or so is doomed. People who are exposed to this constant marketing pressure often have difficulty understanding just how throughly they have been mislead. Trying to counter this pressure is where some of the more extreme anti-phosphate remover statements come from.

Another problem with phosphate removers is that it is still possible to get algae even when the phosphate level is very low. This is not common, but it does happen.

Another problem with phosphate remover is that it distracts people from what is actually important. Algae is not, in and of it's self, a health problem. Algae is a problem because it lowers the FC level very quickly. Clear, algae free, water is not always safe to swim in. It is critical for health reasons to maintain an appropriate FC level. Phosphate remover marketing tends to obscure that fact, and suggest that preventing algae is the only goal.

 

[Aquaclear-NZ]

Without wading into this debate ...again

i agree with the below

Mark,

That was an excellent post and delineates my feelings about this as well. Many chemical treatments are effective at preventing or inhibiting algae growth, but they also have various pros/cons and none is perfect (i.e. works completely, is free or a one-time dose, has no side effects of any kind). Since one needs chlorine for disinfection anyway, maintaining an appropriate FC/CYA ratio to prevent algae growth seems the most practical, but it's really a personal choice (and some heartier algae, such as yellow/mustard, give more challenges).



Richard

 

[floating]

Keeping Chlorine in the water is number one.
if you know your overnight chlorine loss, if you test your water everyday, if you can taste a high CYA, if you why CH aint that important, etc....
you prolly keep chlorine in your pool.

so having a phosphate lvl of 2, 3, 4 thousand aint a huge deal. but for people who put cal-hypo tabs in a trichlor used feeder, who think as long as there pool is clear then they don't need chemicals, who go thru three skimmer baskets a season becuase they only empty them when they swim sober enough to remember too; then phosphates can be a serious problem.

But the big thing to remember is to KEEP CHLORINE IN YOUR POOL. period.

 

[polyvue]

Welcome to TFP, floating...

I don't think anyone here will argue with your final point, but I was mystified by your comment that you could taste CYA. (I mentioned this in a post a while back, but I was joking.) There may be several methods in determining cyanuric acid level; however, the only one I'm familiar with uses melanine, which binds with the CYA and causes it to precipitate from solution, making it visible.