> So, whether you partially drain or not, switch to bleach.

I am going to partially drain this morning although I will only start with a relatively small amount to see what effect it has. The pool store guy suggested about 6 inches of water but I am unsure why draining such a small amount will have an appreciable effect. I was never very good at chemistry at the University but draining about 10% of the water would not, I would think, cause more than a 10% change in CYA. And, as far as the chlorine is concerned, yes I am changing to non-stabilized right now.

> But, you do need to order that good kit.

Amazon lists both the 2006 and 2006C kits. The first is about $50 and the second is about $90, but it gives no information about the differences between them. Do you have any information? I don't want to spend more than necessary, but I don't want to spend less than necessary either. If the 2006C kit is worth the price then that is what I would want to get, but I have no information about why it is more expensive.

I assume, based on your response, that the high levels of CYA in our pool are not dangerous to us as people and are not dangerous to the pool provided I keep the chlorine levels commensurate with the CYA levels. Is that correct?

Thanks again.