I checked my FC last night after everyone was done swimming. It was at 1ppm. ****! I put a half gallon of 10% in the night before. That has been about what has been needed each day for the last few weeks. I guess I've gotten used to cool weather and no swimming. There might be a lot of other people in that same rut. Just a word of caution from my experience.
I added enough chlorine to get it up to about 15 PPM. I checked it quick this morning before leaving. Just used the OTO. It was a nice dark orange so I think I should be ok. I'll have to keep a better eye on it now that we are finally getting some hot weather here in Michigan.