The EPA sets a limit of 4 ppm FC because that is the limit set for drinking water. Does that make sense? You aren't drinking 6-8 quarts of chlorinated pool water every day and skin absorption is not anywhere near that high (97% of the FC is bound to CYA and CYA skin absorption is minimal as described
here). Also, the EPA does not understand the chemistry of chlorine and CYA. They were not aware of the chemical equilibrium determined in 1974 as described in this paper (I know because I've talked to the relevant people in that division that approve disinfection products including those for pool use). I suggest you read at least the introductory section of that paper.
As for state codes and the APSP (formerly NSPI) and NSPF CPO guidelines, you need to understand that much of this is driven by the chlorinated cyanurate industry that claims that "real pools" don't follow the chemistry yet we've got thousands of pools at both The Pool Forum and here at Trouble Free Pool that follow the chlorine/CYA relationship as predicted, when conditions are otherwise conducive to alage growth (i.e. there are nutrients and no algaecides). We don't have a financial incentive to claim that Cyanuric Acid (CYA) levels don't matter, but these corporations that profit from chlorinated cyanurate products (e.g. Trichlor, Dichlor) do.
I and others who are technically oriented on this forum have pored through the scientific literature and found that the chlorine/CYA relationship holds extremely well in almost every case, be it killing of bacteria (
here,
here,
here,
here), inactivation of viruses (
here), protozoan oocysts (
here,
here), inhibition of algae growth (
this paper claimed no correlation, but real pools say otherwise; Sommerfeld never wrote back to me when I questioned this), and oxidation of ammonia and organics (
here) as well as correlation with ORP (see
this post). I've also gone through field study data where the industry makes claims that only Free Chlorine (FC) matters yet I saw that bacteria are killed so easily that you can't even draw that conclusion from such studies and that hypochlorous acid (HOCl) is at least as good a predictor though they never looked at that correlation nor the FC/CYA ratio as a proxy (see
this thread).
You can follow the research and the science for yourself or have someone you know who can follow the chemistry and microbiology tell you for themselves. This isn't anything I or anyone else is making up.
Also, there are chemical facts that aren't taught in
NSPF CPO nor
APSP TECH courses nor found in books or in government literature or state codes or anywhere else, yet they are absolutely indisputable and based on the most fundamentals of chemistry:
For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.
For every 10 ppm FC added by ANY source of chlorine (and accounting for chlorine usage/consumption), the salt level increases by at least 8 ppm.
For every 10 ppm FC added by chlorinating liquid or bleach (sodium hypochlorite) or lithium hypochlorite, the salt level increases by an additional 8 ppm (so 16 ppm total).
Simple math shows that even a pool with a low 1 ppm FC per day usage using Trichlor would have CYA increase by over 100 ppm in 6 months if there were no dilution of the water. Nobody teaches this, and this is what happened in my own pool years ago that got me interested in pool water chemistry when I got no help from pool stores (my CYA went from 30 to 150 after 11 months of pool use over 1-1/2 seasons and the water got dull and chlorine demand went way up from previously being around 0.7-0.8 ppm per day -- the pool is covered most of the time, has an oversized cartridge filter, and minimal splash-out and I was even using PolyQuat algaecide, but only every other week).
I have tried to get NSPF to add the above info to the CPO course, but they haven't done it; I have asked manufacturers to add it to their labels or supplemental materials, but they won't do it (they say are bound by EPA FIFRA rules which are a long and expensive process, but the above are facts not relating to dosing or disinfection claims so can be approved in a quick 30-day process as easily as a company address change). With my experiences, I would not simply trust what a government agency nor industry trade group nor corporation says without verification.
And yes, you are right not to simply trust what anyone, including myself, writes on the Internet. That's why I always try to document my sources, try to use peer-reviewed scientific research whenever possible, and give details of any calculations or logic that I use so you can determine the veracity of what is being written. Most of these details are kept in
The Deep End since they are mostly technical, boring, and not of general interest to most pool owners who simply want to know what to do, not why it works.
Richard
[/quote]
Has anything at all even remotely political happened in Illinois in, say, the past year or so? 
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