White flakes on pool bottom

[Beb5162]

I have a 20,000 gal in-ground, self cleaning, concrete salt water pool with a chlorination cell. I vacuum weekly, and I'm getting a white flakey substance on the bottom of my pool. Is this calcium and what can I do about it?

[aylad]

It probably is calcium--but if you'll post a set of test results (drop-based, no strips please!) for Cl, TA, pH, CH, CYA, somebody should be able to look at them and make a better diagnosis....
Welcome to the forum!!