2 year old in-ground gunnite pool with diamond brite quartz. Lots of scaling. Cracks were repaired on bottom of pool 2 years ago and they are still bright blue while the rest of the pool isn't, making the repair very noticeable. Builder's rep (and diamond brite rep) came over and said its a result of me using tablets raising the CYA too high, and that we need to do a drain, acid wash, and low alkalinity start up to address it. Does that sound right? I had been using the pool store for water analysis and they always said the CYA was about 60. His test was showing over 100.
Am concerned with draining pool too. Can't that cause the shell to float? They said they would refill it right away, though.