Rudimenta
Member
I have 2 ph probes at 1 inch from each other and even with countless calibrations both are never the same and always and I mean always, reading lower then he 3 ph pens, seneye and test kits. Which all read between 0.1 and 0.2 higher within a day or so after calibrating. So don't get to focused on them they are a nice indication but I would never buffer or dose or anything like that before I check with my other devices.