Our wonderful CDC posts new fecal-response guidelines!

Give me a break! Are there no math graduates at the Centers for Disease Control? The absurdity of keeping a public pool closed at “20 ppm” for “12.75 hours”, between pH 7.3 and 7.5 and a temperature of “about 77 degrees”… in order to deactivate all those nasty, bad cryptosporidiosis pathogens in lane two before they swim to lane one or three is truly ABSURD! Yes, we need to create significant Oxidation Potential (ORP) in the water after a fecal accident and, yes, it needs to be kick-butt, but to define the deactivation time as 12.75 hours (heavens, not 12.5 or 13 hours!) is mathematically – effectively and statistically – ridiculous! We at PPOA ask forgiveness, as the CDC is trying hard to make things safer for those swimmers in our public pools; it is just the crazy nature of their false “precision” that troubles us!

Twenty parts per million of “chlorine” (do they mean associated HOCl?) can produce an Oxidation/Reduction Potential of near 850 mV – a truly effective, highly qualitative sanitation value. But so does 16 ppm – even 30 ppm – as the functional value of each, exact residual level declines greatly with the increasing total of readable quantities. Cyanuric acid, along with every tenth decade of pH – and certainly considering the presence of those annoying ammonia compounds of chlorine called chloramine – have huge influences on the work value of the sanitizer in the water. Test-kit readings are simply a working range, not a functioning value! A tenth of a pH decade or 10 ppm CYA can have far more influence on the work value of a free-chlorine residual than a few ppm up or down. (And what does “between pH 7.3 and 7.5” mean? Literally it’s 7.4, not sorta’ but exactly.)

We know that many of our “public” pools are not fitted with ORP controllers, those wonderful automation devices managing the chemical pumps while reading the actual work value… but we must be aware of the working ranges of those variables we can measure. Let’s look:

“20 ppm” is hugely variable in its work value in the presence of many other variables. It can represent the same ORP (oxidation/reduction potential, the quality of the process) as just 2 ppm at a low pH, no combined chlorine and no cyanuric acid, while comparing it to as much as 30 ppm with 50 ppm CYA, a bit higher pH (like 7.6) and a dominance of chloramine.

Finally, and only if we actually “do it right”, we are told we’ll be “inactivating” 99.9% of those nasty pathogen, meaning just 0.1% will be living and thriving, swimming a bit slower but continuously infecting about one out of a thousand of us… So count all those folks in your pool and, if you’re among about a hundred patrons out there swimming, you only have just one lousy chance in ten of getting that deadly cryptosporidiosis!

Those of us who have been swimming from high school (captain of the 1956 team) through college (captain of the 1960 team) and much more since don’t seem to be too concerned about fecal sanitation. Check PPOA articles in our Pumproom Press ~ issues 4, 6, Summer 98 and issue 36. From cheek wash to brown trout, pool stools and baby-Ruth floaters, you’ll understand that our ability to resist contamination in human infestation is pretty doggone’ wonderful. Otherwise, this contributor would surely be sick today, not interested in ever going swimming again nor in writing this piece!