My makeup water quality is about 210 mg/l CH and after only 18 months since the pool was built/filled (two seasons) I have some areas of "discoloration" in my pool with a pebble finish. The pool builder brought out the finishing contractor. He took a sample and the one highlight that the pool builder pointed out is the high level of CH at 1200 mg/l. My testing puts CH at 925 mg/l and I have been a TFP follower since the pool was built with the CSI staying in the +/- 3 range with only some outliers with a high at +.48. And, even though I have no noticeable calcium deposits around the tile line he believes it is due to high CH. I believe since discoloration seems to be only in the areas that I add HCL that it is more likely caused by me adding HCL too quickly. Does anyone have any thoughts either way?
So, with my water makeup at 210 CH and with the extremely high evaporation rate of the Las Vegas, I will have to come up with a game plan to keep CH down to a value to is deemed acceptable for the pebble finish. Even though I can keep the CSI at acceptable values, should there be recommended max CH concentration?