I normally test myself, but went to the pool store to get some acid so had them test my water. All numbers were in range, including CH which was 220. However, there were calcium particles floating in water after the test. Store tried to sell me clarifier and something else I don't remember. They said although my CH was within levels, I had too much calcium in my pool (as he showed me the particles floating in the test kit) and it could cause problems. Just thought I'd check here before I bought anything.