I don't trust myself on the CH test. I put the 20 drops in, and then the 5 drops, and it just SLIGHTLY turns pink, not red. Then, after 20 drops of the next bottle, it is the slightest pale blue (but that might be the sky, or me hoping). I went up to 50 drops and it didn't change, and I stopped wasting my test kit.
Could I have no calcium at all?
My pH is 7.2, FC is 5, CYA is 50, by the way. This is with the 100 test kit from this board.