So do I add CYA...

[awarsoca]

PH 7.8
TA 80
CYA 40
TC 7.5

The TC has dropped from 14+ in the last week but clearly the CYA is below recommended levels for a SWG vinyl

 

[reebok]

Yes it is. I think you answered your own question.
Also, tc is kind of a vague number. FC and cc would be much more descriptive.

 

[awarsoca]

Sorry typo...it was a FC number not TC. (BTW those are last night numbers...CC was 0 two days ago)
The reason I am hesitant to add the CYA is that the FC number is higher than it should be for a SWG Vinyl. I didn't want to add the CYA and hold the FC at the high level unless I needed to

 

[frustratedpoolmom]

It doesn't work that way, the FC will still drop if you aren't adding chlorine.

You should raise the CYA to 70, leave the SWG off until the FC drops where you want it, and then turn it on adjusting the percentage till you find the right setting, to maintain your FC at the recommended range.

 

[awarsoca]

Thanks!