I've been reading and studying and am wondering about CYA buildup from the trichlor tabs I use.
From pool school:
"2. Trichlor - Commonly sold as tablets or pucks that you simply put into an automatic container that passes pool water over them and they slowly dissolve - putting chlorine and CYA into your water and lowers the pH. They are incredibly convenient and incredibly insidious. The CYA that they put into your pool water doesn't get used up, and instead accumulates. Eventually the CYA level will build up to a point that renders your chlorine ineffective. Typically, everything is fine, until one day you start to develop algae and don't understand why."
After 2 seasons of using trichlor, and after a major dichlor shock 4-5 weeks ago, my CYA is 20.
Is there a specific CYA level at which chlorine becomes either ineffective? Or, do we refer to the CYA-FC chart and say that when CYA levels reach a certain point, the amount of chlorine needed to keep the water clean is too high for safe swimming?
At the beginning of each season I raise the water level about 1 foot of my 4.33 foot deep pool. Might this mitigate the CYA levels?
I'm trying to get at how bad my use of trichlor really is.