CYA Fluctuations

baundy

Member
Apr 11, 2024
22
Southeast Indiana
Pool Size
13090
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-20
Just a general question, no specifics. Can CYA increase without adding anything to the water? Or does a CYA "increase" without chemicals just exhibit an error with the testing? I know the CYA testing is somewhat the most "subjective" (when exactly does the black dot disappear?), so if you read a 70 one day and an 80 the next, having added no chemicals, does that just show that you're reading the test wrong? Or is the CYA level capable of increasing without chemicals?