Every once in a while there is an odor of ozone hovering about 5" or so above the water surface of our pool. Why is that? Where does it come from? I use chlorinating liquid and the water is about as perfectly balanced as I can get it:

pH 7.5
FC 5
CC 0
TA 80
CYA 40


I don't notice this smell all the time but when it is there, it's kind of annoying. Is it just part of the pool chemistry?

AnnaK