Quote Originally Posted by Goolsbymd View Post
Waiting a week, what is the reason for that?
CYA can take up to a week to FULLY dissolve. Just a safety precation so you don't overdose.

So the CYA goes through the sand, right? I have a cartridge filter so I would imagine once it is dissolved it's all in the pool?
The undissolved CYA will get caught in the filter, be it sand, cart, or DE and stays there until fully dissolved.

Or does CYA have some kind of don't know how else to say it but like a timed release to take effect?
No, it just gets caught in the filter and slowly dissolves there. Wait a week and retest. It's not rocket science.

Even if you put it in a sock as some do (and IMHO, usually unnecessary, just pour it SLOWLY into the skimmer with the pump running) it will pass though the cloth and some will still end up in the filter and dissolve there. It often is all dissolved in a few days but waiting a week is good insurance against overdosing and needing to drain.