Algae, TA or what?

[CarlD]

Carl, Richard's calculations and analysis of the relations between pH change, TA, off gassing and so on are plausible. I can't verify them yet, but they do fit my own field experience, so that's confirmatory.

My inclination, at this point, is to accept them -- and their implication that low TA is to be desired, generally -- for NON-concrete pools.

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I do think we need to be observant, and see if field reports from PF users confirm or dis-confirm the idea that lower TA (and particularly, lower carbonate alkalinity) leads to greater pH stability.

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But, it's going to be hard (at least for me) to digest all that he's done, in order to get clear in my mind what to tell people.

I do have one question to you all (that is, anyone who bothers to read this section, but particularly the mods and Richard):

How interested are you all in changing pool chemistry -- not just for the 100,000 or so who follow PF and TFP closely -- but for the majority of pool users?

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But it would (in the end) seriously affect BioLab as it exists today. And they drive the NSPF, many commercial pool codes, and the shape of "ideal" pool chemistry.

(As you respond, keep in mind that BioLab probably will read this. When I last checked, several years ago, connections from their corporate network were ALL OVER this site and PoolSolutions.)

Ben Powell

I'm a big believer in doing what actually works, not what I'd like to think works, what everyone says works, or even the mantras I've followed for 9 or 10 years now.

First off, let's divide "the world" into vinyl versus concrete/plaster pools as you suggest and keep this discussion solely to the vinyl (and I presume fiberglass) side. As you point out, the concrete/plaster side has all kinds of issues that may well require different standards than the vinyl side.

So, only for vinyl pool owners I'd like to see us start collecting empirical evidence that Richard's and Evan's low TA theory ("theory" in the scientific sense, not the popular sense) is valid. It will probably take a few seasons but, frankly, even if it were shown to not be valid, I don't see it doing much harm to people's pools or swimming experiences. In other words, it's a safe test for us to run.

In fact, I'll start lowering TA on my pool either tonight or this weekend--it's about 80, so getting it down to 50 should be a snap. Plus I've got my "splashers" to aerate it!

As for the pool chem companies, we are already NOT where they want to be. Even with our current recommendations of TA of 80-125, we tell people that baking soda is chemically the same stuff as "Total Alkalinity Raiser" and that washing soda is chemically the same stuff as "pH Up!" (which also raises T/A). We further tell people to use muriatic acid to lower TA (by lowering pH).

So we already advocate a T/A control system that does not require special chemicals only available from pool companies. If we simply move to advocating low T/A levels it doesn't affect them in any way that I can see.

Our recommendations with regards to when to use chemicals only they can make readily and publicly available: CYA, Calcium, Polyquat 60%, Tri-Chlor, Di-chlor, Cal-Hypo and Sequestering agents, remains unchanged.

So does our recommendations for chemicals to be avoided.

Again, my own limited experience is that I've ONLY ever had a drastic change in pH, or even a constant change in pH where there was a clear, explanable cause, such as the time I came home after 2 weeks and found my CYA at 60 and my pH below 6.8. I had put 4 floaters full of Tri-Chlor tabs in my pool. The good news was I had no algae.....At the time I was not yet aware that Tri-Chlor was heavily acid--that must have been 2003.

So, I guess what I would like to see is a set of TA levels recommended, somewhat similar to the table Richard has attached above, but, obviously with clearer guidelines (Not going for TA=40 and pH=8.0 to get perfect balance! )

Carl