What is the calibration acceptance criteria for pH calibration on a Pocket Pro or Pro+?
Pocket Pro and Pro+ pH calibration acceptance criteria
The acceptance criteria for the pH calibration slope is 90-110%. If the meter displays "SENSOR?" after calibration, the calibration slope is between 85 - 90% or between 110-115% of nominal (-59.16 mV/pH). If the meter displays "ECAL" after calibration, the slope is either <85% or >115%. These tolerances cannot be changed.