Pool store person said may need to add calcium increaser if level is too low. (haven't tested mine yet as trying to just clear it up right now). He said if there is not enough calcium in water that it will be pulled from "wherever" it can, like the liner and make it brittle.
I have read on here that calcium hardness does not matter in a vinyl liner. Why is that? and is he feeding me "pool store" Poo?