I have a Hanna pH electronic meter from my reef tanks days. You stick the thing in the water and and two electrodes measure. Was some 70 bucks, supposed to be **** accurate.
Problem is it reads .1-.2 HIGHER pH than phenol red test kit from K-2006 and the HTH kit from walmart. Tonight K2006 kit said 7.5, pH meter said 7.7.
What to believe? I know the phenol test is about as simple as it can be, but I'm confused about the wide difference.
Could the free CL- ions be messing with the electronic meter? Doesn't make sense. I'm using trichlor tabs for now but really want to get a full handle on what my water is doing. Test results via K-2006:
CC - 0
ALK - 100 (using thrichlor tabs for now via chlorinator, want them to up CYA)
CH - 180
MODS - if you want to move this somewhere else, feel free to do so.