The calibrate (calibration) of a meter in order to ensure that the meter the correct readings.
Theoretically, the measurement of pH is a complex issue and using the glass electrode is measured a voltage which is converted into a readable pH value on the display.
The calibration with pH 7 is intended to set the meter. Milli volts at 0 = pH7
Without calibration, the measurement can never work properly.
Beware: The electrode only works well if it is wet.
If the electrode has been the first 8 hours in additive solution places for calibration or use. Longer drying time
This depends on the degree of use and on the spot. pollution, but at least every month.
Even if you get the meter for the first time and after each cleaning, calibration is necessary for a good measurement result.
Place the pH electrode in the pH 7 solution and wait for the reading to stabilize.
The electrode now gives a value of pH 7.01 again, if this is not the case, the instrument enables you to this value.
How You must set the instrument depends on the type of instrument, consult the manual for the meter.
Depending on the type, set the meter manually (turning a screw) or automatically (using a key combination) in.
pH 7 is exactly centered on the pH scale.
A pH meter must therefore always be calibrated first (calibrated) to pH7 to be in order to ensure that the measurements are carried out optimally.