8
3 CALIBRATION
3.1
Important Information on Meter Calibration
When you re-calibrate your meter, old pH, Rel mV and mV calibration points are replaced on a point
by point basis. For example, if you previously calibrated your meter at pH 4.01, 7.00, and 10.01, and
you have now re-calibrated at pH 7.00, the meter retains the old calibration data at pH 4.01 and pH
10.01. To view current calibration points, see Program P2.0 in the SETUP section on page 26.
To completely re-calibrate your meter, or when you use a replacement probe, it is best to set the
meter to its factory defaults and re-calibrate the meter at all points. To reset the meter to its factory
defaults, see the SETUP section, Program P5.0, page 34 (for pH 300 meter) or Program P6.0, page
37 (for pH 310 meter).
3.2
Preparing the Meter for Calibration
Before starting calibration, make sure you are in the correct measurement mode. When you switch
on the meter, the meter starts up in the units last used. For example, if you shut the meter off in “mV”
units, the meter will read “mV” units when you switch the meter on.
Be sure to remove the protective electrode storage bottle or rubber cap of the electrode
before calibration or measurement.
If the electrode has been stored dry, wet the electrode in tap
water for 10 minutes before calibrating or taking readings to saturate the pH electrode surface and
minimize drift.
Wash your electrode in deionized water after use, and store in electrode storage solution. If storage
solution is not available, use pH 4.01 or 7.00 buffer solution.
Do not reuse buffer solutions after calibration. Contaminants in the solution can affect the calibration,
and eventually the accuracy of the measurements. See page 43 for information on our high-quality
pH buffer solutions.
