Does high CYA protect swimmers from effects of high chlorine?


LifeTime Supporter
Apr 30, 2015
Wake Forest, NC
Since the higher your CYA, the less effective your FC is in fighting algae etc and you need higher chlorine levels if you need to slam does high CYA protect swimmers who may be allergic to chlorine and or may not want their bathing suits faded from high chlorine levels? I have read instructions in the past, on shock products, that indicate not to go into the pool when chlorine is more than 5 ppm. If my CYA was 100 my FC goal would be 5 to 13 ppm but if I had no CYA and had an indoor pool then my FC goal would be 1 to 3. Would both of these scenarios have the same effect on people, bathing suits and vinyl liners? Thanks. Just curious.


Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
Aug 10, 2012
Not quite. With no CYA, 3 ppm of FC would be much harsher, very harsh actually, than FC of 39 and CYA at 100. We SLAMed last summer with CYA at 70 and FC at 28 for about 2 weeks. We swam every day and nobody even noticed the difference from the normal FC level of 8ish.