Thanks Dave. The water does look great by the way.
I was going to ask about the box of shock I have (Bioguard Burn Out) but I looked at it and its that Caly Hypo you said was not a good choice. The pool store (who built the pool) suggested 1 per week and 2 after a big party. I've not done it for several weeks. Is this shock an alternative to adding chlorine? I get confused reading about shock and what is really does. Especially the Best Guess table - it has min FC, max FC and shock FC.