Hi Jim,

I think a lot of fears come from the misunderstanding that it's the chlorine (higher levels) that causes problems with bather comfort. In fact it's low chlorine levels that causes the problems and PH levels have way more impact on eye comfort etc. Smell that chlorine smell ..that's cause by high CC levels and inadequate FC. Now high chlorine might eat your bathing suit if you don't rinse it but as I understand it it's hard to hurt people with Chlorine until you get very high levels. With CYA you are trading effectiveness for longevity. Chlorine loses some of it's "work value" when attached to CYA. So where .1ppm with no CYA might kill a bug in 5 seconds with a CYA of 70ppm it might take 20 minutes. That's why you need to run higher levels of residual chlorine. It's like having a surplus in your bank account or an insurance policy. If it's needed it gets used and if it isn't needed then it sticks around instead of being eaten by the sun. The fact that you have algae in the corners demonstrates that the CL levels are too low. Shocking isn't a maintenance item but rather a method to combat a specific issue such as algae blooms or a CC level of more than .5ppm I believe. I have a CYA of 55 and float my chlorine levels between 4-9ppm. It was 4ppm last night and I added another 4ppm which will last me a couple of days. Everyone remarks on how nice the water feels and how they don't like high chlorine levels in pools ..I just smile.