Quote Originally Posted by mastamoon View Post
I think my red/yellow test kit was lying to me.
They don't. OTO is not the most accurate test, but it is the most goof-proof. It said you had chlorine: you had chlorine.

I can't remember if your a guy or a gal . . . but I learned the hard way (working with 100's of lifeguards over the years) that some guys, who aren't color-blind, are color-dumb and have to be trained to pay attention to colors. I hired a guy like that -- did color blindness tests with him, which he passed fine. But he was reporting bogus test results on customer pools because he just had never bothered to pay attention to color differences. Took 6 weeks of hounding him, to get him to make the effort to make the distinction. I ran into the problem multiple times over the years. I actually never had a guard who was physically too color blind to read the kits, but we found a number who couldn't be trusted to pay attention to small color increments.

Dunno if that's the issue, or not. But there are other potential problems. If you have moderate chlorine, very low CYA, and very high pH, your chlorine will be ineffective.