Hello everyone! Haven't been on here in forever because I simply NEVER have water issues anymore. But now I finally have an issue...maybe. Since the start of the season (opened May 1st), I have added 3 of the 4 pound canisters of HTH stabilizer. I hung the sock full in front of the return... blah blah blah. Lets play devils advocate and pretend my CYA upon opening was 0 (even though it couldn't have been). According to the calculator, this should have brought my CYA up to at least 45 ppm. Well, the black dot is, well, black. I filled all the way to the top of the tube, it doesn't change in clarity at all. I do know how to do the test and have been doing it for years. I haven't had to add any water this year. And certainly haven't drained any. Water is clear. No CC's. So, any clue as to what's going on?