I thought that too so I have also used my PH test kit and it confirms my findings.
a side note: the meter did come with an accuracy guarantee of +- 0.1 PH which should be more than adequate. I also have calibrated it like it says to with PH 6.86 standard buffer solution of phosphate, and then tested it in a PH 4.01 standard buffer solution of borax. It required an initial adjustment but has held the calibration since.
a side note: the meter did come with an accuracy guarantee of +- 0.1 PH which should be more than adequate. I also have calibrated it like it says to with PH 6.86 standard buffer solution of phosphate, and then tested it in a PH 4.01 standard buffer solution of borax. It required an initial adjustment but has held the calibration since.