My pH reads at 5.5 - 6.0 currently. I test it when I top off and I test when I drain. It fluctuates, but so far within an "acceptable" pH range. I also always put two gallons of water in my mixing container, mix micro in with a gallon of water, then bloom with a gallon. I had heard that mixing them directly could cause an issue so I avoid it like the plague. My BlueLab is new (4 months) but I'll try replacing the battery. I wouldn't imagine that would be the issue, but I'll try anything at this point. I've thought about just never going above 1/2 strength nutes for this strain, but I was afraid I'd starve it to death.....