No CYA

[AnnaK]

It's possible that the CYA is being backwashed out of the filter before it has fully dissolved. We normally recommend that you start with a clean filter, then add CYA via the skimmer and wait a good week before backwashing, if that's necessary. Or add CYA using the sock-in-front-of-a-return method which doesn't get affected by backwashing.

Until you can get a testable CYA level your SWCG is working too hard. I'd turn it off and go with straight bleach or dichlor powder for a while.

[Watermom]

I agree with Anna that you should turn off the SWCG for now. 24 lbs. of stabilizer in your pool would add 95ppm of CYA. Since you don't know how much may have been backwashed out, I wouldn't use any stabilized forms of chlorine until you can verify the reading, so I would use bleach and not dichlor.

Welcome to the Pool Forum, by the way!

[wilcfr]

Okay so I tried my version of the CYA in the sock trick and it seems to have helped. The CYA level is now at 30 which is an improvement. The Alkalinity on the other hand is still a mystery. We put 1 gal of Muriatic Acid in the pool yesterday. Today we checked the pool and found the pH down 4 points to 7.3 and the Alkalinity went up from 270 to over 300. We are going try aeration to see if that helps.

[Watermom]

I can't see how that is possible for the alk to go up. Go ahead and add a little more acid and then aerate the pH back up and repeat the cycle until your Alk is where you want it.