I have an inground pool with a vinyl liner. I've been doing regular testing with my numbers in "acceptable" ranges all summer. Recently I started wondering what effect calcium hardness has on the liner. My CH started at 210 in spring and is at 250 now. My readings from today are below if it matters, but I'm curious where CH needs to be for vinyl

FC = 2.6
CC = 0.0
TA = 180
CH = 250