Quote Originally Posted by Winicott View Post
Copper is 1

I am thinking that I should shock THEN raise CYA since the shock threshold is lower when the CYA is low Or are we looking at Polyquat (Are you sure 'Polyquat' is not really a swear word?
Do *NOT* shock (raise the chlorine level suddenly). You NEVER want to do that when you have metals in the water, unless you have a specific case, and are trying to drop all the metals to the bottom --you can do that with iron, but not copper.

Polyquat is a good backup. It not only will help filter the metals out, as they precipitate, but it will reduce the need to 'shock' to control algae.