Please accept my apologies for the late response.

Thank you both for your replies. I am keeping the pool at about 28 CYA and using liquid bleach. It appears to hold reasonably well although I might add pucks to the feeder to balance the high PH of liquid chlorine and then very slowly let it rise to 50 before draining back.

I hate adding water because in Hawaii it seems to contain a lot of ferric oxide (iron rust) due to our volcanic soil and rock which is mostly ferric oxide. This creates stains. That means either I have to go with the ascorbic acid regime or add sulfuric acid. I am testing both methods, sulfuric acid seems to be better as it precipitates out versus putting it into solution and then into the filter to be backwashed out. The problem with ascorbic acid is that as it stays in solution and one is constantly adding metal out. That starts to get expensive. See my question on sulfuric acid.

Aloha