My cya is 100-110, previous owners probably relied on tricolor pucks it would seem. Was going to see if it went down over winter. I have a pebble tec pool with multicolored tiles on rim. Horrible scaling build up. I have used pumice ( go through it way too fast), de scaler spray ( not a chance) paint scraper ( lots of forearm fAtigue) and recently a chisel and hammer ( use correct angle to avoid tile chipping). Really looks like hell. Any thoughts?