Hey guys. I'm curious about safe levels of free chlorine for swimming, given certain CYA levels. I read some of Chem Geek's article on the chlorine/CYA relationship and most of it was well over my head. I did gather some of the info I was after, I think, but I wanted to verify whether I'm interpreting correctly. It seems to me that FC levels can be VERY high and yet still be safe to swim in, given basically any CYA level within the suggested 40-80ppm. Is this correct? From one of the charts in his paper, I read that if my FC is 50% of my CYA level (FC=25 @ CYA of 50, for example), the equivalent FC without any CYA would still be less than 1ppm. This would mean that @ 50ppm CYA, I would have to have pretty astronomical FC levels for the water to be questionable to swim in. Am I correct with all this, or am I missing something?
The link for the paper/article I'm referring to is here: http://standards.nsf.org/apps/group_pub ... nt_id=5891