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4. pH Calibration
A “
” in place of the decimal point indicates that the pH readout is not
calibrated, or a
past calibration has failed. The “
” will be removed once
a full two-point pH calibration has been successfully performed.
4.1 Calibration
1. Switch the
Aqua-DP
on.
2. Select pH Mode (see section 2).
3. Plug the pH sensor into the BNC socket (this is the metal socket). For
automatic temperature compensation, plug the Dissolved Oxygen
sensor into the Dissolved Oxygen socket (this is the 6-pin plastic
socket). If the Dissolved Oxygen sensor is not connected, then the
Aqua-DP
will use manual temperature compensation.
4. Ensure that temperature has already been calibrated, or manually set
(see sections 6.1 and 6.4). NOTE: If the decimal point in the
temperature reading is replaced by a “
“, then the temperature
readout is not calibrated.
5. Remove the wetting cap from the pH sensor.
6. Rinse the pH sensor in distilled water and blot dry.
7. Ensure that you are using the buffers which have been selected for
automatic buffer recognition. See section 8 for a detailed explanation.
8. Place the pH sensor into a small sample of pH7.00 (or pH6.86)
buffer, so that the bulb and reference junction are both covered. See
the diagram over the page. The Dissolved Oxygen sensor can be
placed into the same sample, or a separate beaker of water that is at
the same temperature as the buffer.
