Interesting information, thanks. Didn't realize CYA helped with the corrosiveness of the water.

The pool is usually covered when the sun is out, but I do occasionally have to fight to keep FC up, so who knows.

To clarify though, even if my tests aren't catching it, I shouldn't need to add raw CYA if I'm using trichlor tabs in an auto-chlorinator (which runs all night.) The CYA must be getting in there, and my understanding is that once it's in there, it doesn't go away until you dilute the water.

Love the forum!

E