So, my CYA is 45 and I've been maintaining the pool above 5ppm. I had it at 10ppm when the CYA was 60 (the constant rain brought it down). Still, we're going through chlorine faster (for the third time since starting this method this season). I tested before adding chlorine and it was 3.5ppm, so for kicks, I added a gallon of 10% and 2 hours later, it's 7ppm. So, we're dealing with algae again (pool is still clear). No one has even went swimming for 2 weeks. All other tests are normal and no combined chlorine.
I've been very careful with the CYA test. I study it in good lighting for like 15 mins until I'm sure I can no longer see the dot. So, what gives?