Below is procedure of manual pH calibration from Water Analytic:
1.Select Manual Calibration
2.Place the probe in the first buffer. As opposed to auto calibration, it is okay to press Enter without waiting for the probe output to settle down. The next screen will display the current output reading of the probe. The pH is calculated from the mV reading based on the operation of a perfect probe at 25 0C, i.e. pH 7= 0 mV and the voltage increment is 59.16 mV/pH.
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