Hanna Instruments HI99163 Instruction Manual page 11

The LCD displays the pH value (auto‑
matically compensated for tempera‑
ture) on the primary LCD, while the
secondary LCD displays the sample
temperature. If measurements are
taken in different samples successively, rinse the probe tip
†
thoroughly to eliminate cross‑contamination.
For better accuracy, frequent calibration of the pH sensor
with the meter is recommended. In addition, the meter
must be recalibrated whenever:
a) The pH electrode is replaced.
b) After testing aggressive chemicals.
c) Where high accuracy is required.
d) At least once a month.
e) After cleaning the sensor.
† The probe tip should be rinsed with purified water (reverse
osmosis, distilled, or deionized) before and after placing in
any solution (buffer, storage or sample).
pH calibration
Enter calibration mode while in pH measurement mode.
Place the sensor into the first calibration buffer. If perform‑
ing a two‑point calibration, use pH 7.01 (pH 6.86 for NIST)
buffer first. The meter will enter the calibration mode,
displaying "pH 7.01 USE"
"pH 6.86 USE" for NIST).
Follow directions for single and two‑point calibration below:
Single-point calibration
1. Place the probe in any buffer from the selected buffer set.
The meter will automatically recognize the buffer value.
2. If the buffer is not recognized or the calibration offset is
out of the accepted range "---- WRONG" is displayed.
3. If the buffer is recognized "REC" is displayed then
"WAIT" until the calibration is accepted.
and tag blinking (or
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