Did a search and found that CYA will not typically move except by dilution, or draining water.
I test weekly, and have been chasing Chlorine too, even with SWG, so starting SLAM. But I've used 7# of CYA in last 2 months. Its been a weekly add. We've had some rain, a couple heavy storms, but not to where we have had to drain pool. Rain gauge says less than half inch in the last 2 weeks.,
Our poolmath is set with goal of 70 CYA.
Weekly readings in June have been
6/4 40, added per PM
6/12 30, added per PM
6/18 30 added per PM
6/26 50 added per PM
Full test from yesterday
FC 2.5 (my testing tube is collecting black residue on the bottom?
Alk 90, added acid to 7 and will aerate to bring ph back up.
I know CH is over my desired, holding off doing the drain until I kill off whatever is consuming FC
I'm using granular CYA, putting in sock in skimmer. That is empty in a day. Have not cleaned filter weekly, as the pressure gauge didn't require it, but cleaning monthly. Been adding supplemental 10% chlorine as well, for what Pool math recommends for our desired 70 ppm CYA.
SWG isn't keeping up, been hot and sunny, but running 8 hours at 100% daily isn't keeping FC where I want it.
Your thoughts on the CYA usage?