If ... you have a phosphate problem

[lucy0909]

This off topic side conversation has been split off of this post. JasonLion

New to TFP but have some advice anyway.

Leave the pool alone for about 3 days. Your chemistry is bouncing and pools will do that. When chemistry bounces, the owner is literally chasing it's tail. You'll never have a clear concise readings. As long as your FC levels are good and steady, you don't have to worry about going green.

I noticed your phosphate levels jumped. Do you live in a rural area or is there fertilizer being used on your (or nearby) lawn? If the phosphate level is REALLY that high, then you could need to use a phosphate reducer on a regular basis. I'd check the phosphate level again in about a week.

 

[lucy0909]

We don't worry about phosphates. Reason being, is that we focus on killing and preventing algae with proper chlorination. If there is no algae, or it is dead, it cannot use the phosphate for nutrients, no matter how high the phosphates are.

As Woody mentions, her FC/Cya level will allow Algae to Bloom with vigor at that low level of 2.

Lol ... I'm a bit amused. Actually ... I don't think phosphates are a problem in this case as much as I think there is definitely a chemistry bounce going on right now. I also think the test results prove this. A pool will react to every single thing that is introduced to it. Treating a pool with balancers and adjusters every day will send any pool into a bounce cycle causing the owner to chase it; which never works out. Chemistry can literally change from hour to hour; day to day. And here's the thing ... you all know it.

Now unless somebody in the forum actually has a chemistry degree, I don't know that I'd come off as unequivocal all-knowing authority about pool chemistry.

Just know this CGSteve:

- If your phosphate readings increase and your chlorine consumption dramatically increases ... you have a phosphate problem.

- Leave the pool alone for a couple of days and then make your adjustments.

- There is such a thing as having too much CYA present in the pool. It'll cause chlorine lock and then you've got a whole other problem on your hands. CYA is important to establish but it's not a Hail Mary in preventing algae blooms.

- There's a difference between FC and TC (total chlorine). Your FC is what keeps the pool from going green; not necessarily in total conjunction with CYA levels. <-- See above.

God Speed and Good Luck!

 

[Swampwoman]

Re: Newbie With Concerns - Leslie's Free Testing

Now unless somebody in the forum actually has a chemistry degree, I don't know that I'd come off as unequivocal all-knowing authority about pool chemistry

Lucy, we are very fortunate here to have some very fine scientific minds who have doggedly researched issues of pool chemistry and who have helped formulate what we call the TFP method, which is in fact based on substantial research into the cya/chlorine relationship. I am not one of them, though, rather, am a test subject and the proof is in my pool

There are some nuances in your post that do not quite align with the teaching of TFP and that have been vigorously discussed in the past with ample referencing to research...you can find many of these discussions in the thread called the deep end. Eg. Phosphates. Have a dig

I agree wholeheartedly than folks without a clear understanding of the readings, additions, and chemical interactions can chase their tails, especially if guided by the type of pool store that believes half-truths of mfgs or does not have the benefit of context. BUT the whole object of TFP is to empower the pool owner to understand and control their chemistry in a proactive way to avoid problems...so the notion of "leaving it alone for a few days" in this case with Free Chlorine much lower for the CYA level than what we know to be adequate isnt as helpful as you oerhaps meant it to be. Had you said only worry about getting your FC up, then THAT would be helpful, for example, and perhaps that's what you meant.

For a CYA of 60, CGSteve, you want to do exactly as Patrick says...minimum of 5 FC, does to 7 FC. Maintaining those levels for a CYA of 60 mean you generally will not develop even nascent algae (and ergo, your phosphate level will not matter because dead algae spores cant eat phosphate )...and more importantly, your water is sanitized.

PH is also worth controlling if it were higher, but you tested at 7.6...if it climbs toward 8, bring it back down.

Ultimately, for a plaster pool. Once you've read up a bit and gotten comfortable with testing, you can use the pool calculated to see if you CSI (calcium scale index) is within the parameters to nicely maintain your finish and overall balance.

Welcome and cheers to imminent summer!

 

[Patrick_B]

Re: Newbie With Concerns - Leslie's Free Testing

Ok Lucy, You've made your points about phosphates being a problem here. I've got some points and questions for you as well, but arguing this, and our backgrounds or other particulars could not be done in the original thread. Doing so would be hi-jacking and derailing the subject matter completely.

I urge you to watch the thread this came from, and you'll see us help the OP fix this pool without us ever addressing the Phosphates. Just as we have with thousands and thousands of other pools. There is no problem with a "chemical bounce" or "Chlorine Lock", (Myth) and the Cya FC ratio is anything but a Hail Mary pass or wild stab. It's absolutely proven, but most importantly, it's proven in the many thousands of pools that have been turned around, and remained pristine with the simple methods we teach.

Moved into a suitable place. JasonLion

 

[JasonLion]

lucy0909, I'm interested in what you are calling a "bounce cycle". This doesn't correspond to anything I have ever heard of.

Also, there really isn't such a thing as a "phosphate problem". That is a myth made up by the people who sell phosphate remover, designed to justify unneeded expenditures on their products. If you maintain an appropriate FC level you will never get algae regardless of your phosphate level. My phosphate level is over 2,000, and has been much higher in previous years, yet I haven't had algae in almost five years, and use noticeably less chlorine than the average for people on the forum.

 

[Patrick_B]

I have some questions for you as well Lucy...

1. Since you mention it, what is your background? You take the stance, that we perhaps aren't qualified to make these calls about what is, or is not a problem, so tell us what qualifications you have.

To answer your question, I do not possess a chemical degree, but I have nearly two decades with a very extensive background in water treatment that is a good deal more complex than Pool chemistry. That said, many of the same principals apply directly to pools, and what I do for a living. I've had AG pools for a number of years, and I built an IG pool last year. I've only used the principals we teach here to keep my pools, and I've never tested for Phosphates. I've had nothing but success, never had Chlorine Lock, and the only bounces I've had, were ones I created with the required, and carefully controlled chemical additions. As for those, the only things I've ever added to any pool I had were Bleach, Muriatic Acid, and Cyanuric Acid.

Please tell us more about your background/experience, and pools you've owned or treated.

 

[woodyp]

Between chemical bounce, chlorine lock and phosphates---we're all DOOMED! lucy0909 is highly invited and encouraged to delve into searching this forum for all these topics which have been discussed and more importantly--------disproved----- ad nauseum.

 

[BoDarville]

It is true that phosphates are a food source for algae, but here's a simple analogy that puts this into perspective as to why phosphates don't matter in a properly chlorinated pool: You can have hundreds of pounds of meat in a meat locker and several hungry lions, tigers, bears, wolves, etc. outside the meat locker. The physical barrier of the meat locker serves as protection for the meat much like chlorine serves as protection against algae. You can add more meat to the meat locker but, as long as the physical barrier of the meat locker is maintained, the animals on the outside cannot get in. It doesn't matter how much meat is in that locker. Likewise, if the proper chlorine is maintained in a pool, algae cannot get in and survive in that pool regardless of the level of phosphates.

 

[chem geek]

Now unless somebody in the forum actually has a chemistry degree, I don't know that I'd come off as unequivocal all-knowing authority about pool chemistry.

Have you looked at the posts and references to peer-reviewed scientific papers in respected journals, especially in The Deep End (where this thread was moved)?

Algae are ultimately limited in their growth rate by sunlight and temperature where there are ideal ranges for each. It doesn't matter how many algae nutrients (phosphates and nitrates) there are, algae will simply not grow faster than is possible given the sunlight and temperature. If one has a sufficient active chlorine level (which is proportional to the FC/CYA ratio), then the chlorine will kill the algae faster than this maximum growth rate. So the level of algae nutrients is irrelevant if one maintains a sufficient active chlorine level.

Figure 1 in this paper gives a rough idea of the maximal algae growth rates as a function of temperature. The generation time, which is how long it takes to double in population, is a little over 5 hours at 86ºF but drops down to a little over 12 hours at 59ºF. Algae can still grow even near freezing temps, but the growth rate is much slower (someone on The PoolForum saw algae slowly growing under their frozen-over pool!). Note that these numbers are maximums assuming ideal nutrients and sunlight. This link in Figure 3 shows growth rates are temperature-dependent in a very species-specific way. The Monod equation is the most common one used describing the limit to microorganism growth rate as a function of nutrient level, but all such models have a maximum growth rate limit. So your implication that algae growth is somehow unlimited as you add more and more nutrients is simply false.

I've had over 3000 ppb phosphates in my pool and there is one member who has had over 30,000 ppb phosphate due to extensive use of HEDP metal sequestrant, yet the pools remain algae free and have normal chlorine usage.

Now I will say that such pools are "reactive" in that IF you let the FC/CYA level get too low then the algae grows at a fast rate and will deplete the chlorine and then grow at its maximum limited rate (from sunlight and temperature). This is why I put phosphate removers in the same category as algaecides. They are only relevant to inhibiting algae growth if the active chlorine level is too low. That is, they are an insurance policy -- they are not necessary and are extra cost, but if you don't think you can maintain an active chlorine level through proper regular dosing, then you are free to do what you want and spend more money on such "insurance". All it will do is slow down algae growth so that when you restore the proper chlorine level you won't need to use as much chlorine to get back to normal.

 

[Saturn94]

....I've had over 3000 ppb phosphates in my pool and there is one member who has had over 30,000 ppb phosphate due to extensive use of HEDP metal sequestrant, yet the pools remain algae free....

I also use HEDP on a regular basis and suspect my phosphates are quite high. But like your friend, I maintain proper CL/CYA levels, so no algae.

Having the SWCG makes it easy to maintain proper CL levels without worry that it will dip below the minimum recommended level.

 

[JamesW]

Any sort of chemistry "bounce" (unpredictable fluctuations from too high to too low) is due to someone adding chemicals without really understanding what they are doing. The keys are good chemistry readings, a good understanding of the existing water quality, a good goal for what you want to achieve and an understanding of how to get there.

Chemistry levels can be quite predictable and stable when you know what you're doing. I don't think that there is much value in describing any pool as inherently "bouncy".