Hi Polyvue, I think my tester is even older and cheaper than that. It only goes to 3.0 and says that 1.0 - 1.5 is "IDEAL". The 5.0 readings come from the BTDG's best guess or the Pool store. I have been looking for a new tester but haven't found anything in the pool stores that go over 5.0, Which makes me wonder how some of these members are measuring readings like 7.0 etc. I am convinced as you stated in your previous post that FC levels between salt water systems and traditional chlorine systems are apples and oranges.

I went for a swim last night with a FC reading of 1.5 - 2.0 and had no eye irritation for the first time in probably 3 seasons. The bottom of the pool did feel slippery, which rather surprised me. I had turned my SWCG settings to 5 hours at 50% and was seeing 2.5 - 3.0 FC, so as an experiment I tried 5 hours at 40% which is what I swam in last night. Sooooo, assuming that the slippery bottom was a result of too low of a reading, I turned the setting back to 50% and will see what happens tonight.

I am not sure how to test for CC's, however the TC and the FC have had the same reading since I re-filled the pool on May 7th.