You should be good to go on the 2 point calibration. My Hanna's PH probe only last alittle over a year with cleaning, calibration and daily use. They cost half what the pen cost to replace. If it checks with the 7.01 your good.
LOC NAR on probation Reviewed by LOC NAR on probation on . Hanna Ph pen So i recalibrate my Ph pen using the 4.01 and 7.01 solutions. I did the 7 first then the 4, i also have the 10.01 solution but i use either the 4 or the 10, i used the 4 because well my ph is going to be right between 4 and 7 so i figured that would be the most accurate calibrating method. Once all is set and done, i wanted to test how well it was calibrated so i put it in the 10.01 solution and it reads out 9.73.... Is that bad? or is it just calibrated for the low ph? and not for the high ph? Rating: 5