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If most state regs aim for 3 ppm chlorine and max 5, why is it safe to maintain and swim in chlorine levels higher than this, say 6, if CYA is higher than 35?
I am sure there is a logical answer but I do not know what it is.
Looking forward to your explanations.
Seems to me that "safe" Cl levels would depend on your CYA level. Simply saying "3ppm of Cl is safe" sounds wrong... what if your CYA level is 10000? Will the 3ppm of chlorine be as sanitizing as if your CYA level was at 30-40? At what CYA level does 3ppm of Cl become ineffective enough for public pool use?
State regs limit cya levels to 80 ppm or 100 ppm. NY forbids cya, unless you file for a special exception with the dept of health.
State regs also require that the chlorine feeding device be capable of introducing certain amounts (lbs) of chlorine per day. Florida for instance requires 1 lb/5000 gallons. California requires 3 lbs/10,000 gallons.
Ben's best bet levels are based upon his experience of many years of doing this. Fortunately you are able to apply this to residential pools also.
I have seen these same regulations as well as studies for chlorination of drinking water http://www.edstrom.com/DocLib/MI4174.pdf. There is evidence that levels up to 10 ppm are safe to drink (in lab mice at least) and there is 0ppm of CYA. Seems to me, common sense steps in and if you can safely drink up to 10, you are probably safe to swim in much, much higher chlorine levels.
Thank you all for your help.
Now I am at least able to explain to all who ask why this is so and put their pool shop/pool maintance persons stories of being poisoned to rest.
Although in all probability they still will not believe me.