I bought this house a little over a year ago. CYA was a 70-80 from heavy Tri-Chlor use. I drained 2/3rds of the pool to get the CYA down and then learned at the first half of last summer that I could not keep up with chlorine demand with tabs, etc. I found this site and switched to BBB. At that start point, I had a CYA of 50ish. I have been chlorinating with bleach based on that number, keeping the chlorine level between 4-8ppm. We use LOTS of chlorine and today, I tested my CYA and much to my surprise, it's 0. Yes, zero, or at least not detectable. This certainly explains the high chlorine usage.
Shame on me, I really didn't think the CYA would change all that much from just adding water due to evaporation, backwashing, draining off some after big rains and such. Obviously I was wrong. I was not checking my CYA regularly. In fact, I don't think I have checked it since end of summer last year.
So, after feeling like CYA is BAD last summer, now I'm left without the knowledge of how much is GOOD. Please advise.
I am in the process of adding Borax (lowering the TA and aerating to get the PH back up). I have long term plans for a SWG but I don't know if that will make the budget this year.
TF-100 test kit