FC - 5
PH - 7.4
TA - 100
CH - 475
CYA - 60
My CH has gone up from 400 last month to about 475. Wondering if this has anything to do with rain? I had replaced some water that evaporated over the last couple of months, but it was only about 3-4 inches worth. (Rain filled the pool to the top tile mark, but it drained to about 1/4th mark on the 6 inch tile, then i filled it up).
Should i replace some water? Pool calc says 16-26% for a 350-375 range for CH.
I have some scaling on the tile as well, but easily rubs off with the eraser.