The only chemicals that have ever been in my pool in addition to the two forms of chlorine already mentioned are Acid, borax, and bleach. After the initial acid washing and needing to raise the PH, chlorine and acid are the only things I need in my pool. My PH creeps up and I usually need about 1/4 to 1/2 gallon of acid per month to keep it at 7.6.

As for an automatic water line, yes I have one. Although it is possible that I have a leak, I really doubt it. We had some heavy rain last week and it filled the pool up. A week later, it's still very full and I know the auto fill hasn't kicked in. When I first had the pool remodeled last year, I quickly spotted a leak as the fill line was almost always on and the water level would drop pretty fast.

So I am thinking that I need to up my CYA to at least 50 and then look at the Autopilot 60.