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3) For pH Calibration buffer solutions, we recommend that users replace new buffer solution after
10 to 15 times of use to keep the standard buffer’s accuracy.
Do NOT pour the used calibration
solutions back into the solution bottles in case of contamination.
4) When calibrating strong basic solutions (pH>10), use 7.00 pH and 12.45 pH to calibrate; When
measuring strong acidic solutions (pH<4), 7.00 pH and 1.68 pH should be calibrated.
5) For the self-diagnosis information, please refer to the table below:
Symbol Self-Diagnosis information
Potential problems and how to fix
The pH calibration solution
cannot be recognized by
the meter.
1.
Make sure the probe is fully immersed in the
calibration solution.
2.
Check if calibration solution is expired or polluted.
3.
1st point of pH calibration must be pH 7.00 or 6.86.
See 6.2 (1).
4.
Please check whether pH electrode is damaged or
broken. If so, please replace with a new one.
5.
The glass bulb or junction is severely
contaminated. Please use a soft brush with soap
water to clean it thoroughly. Then soak it in 3M
KCL 3-5 hours before performing calibration again.
6.
If none of the above, please contact us at
Is pressed before
measurement is fully stable
Wait for
to come up and stay on screen
before pressing
During calibration, readings
being unstable for over 3
minutes
1.
Please check whether pH electrode is damaged or
broken. If so, please replace with a new one.
2.
The glass bulb or junction is severely
contaminated. Please use a soft brush with soap
water to clean it thoroughly. Then soak it in 3M
KCL overnight before performing calibration again.
3.
The electrode is aged (used for over a year and
has a much slower response). A replacement is
needed.
4.
If none of the above, please contact us at
pH electrode zero electric
potential out of range (<-
60mV or >60mV)
1.
Check whether pH buffer solutions comply with the
USA or NIST standard.
2.
Check whether pH buffers are expired or
contaminated.
3.
Please check whether pH electrode is damaged or
broken. If so, please replace with a new one.
4.
The electrode is aged (used for over a year and
has a much slower response). A replacement is
needed.
5.
The electrode is invalidated (Er4/Er5 repetitively
appears, and problems 1, 2, 3 are excluded). A
replacement is needed.
6.
If none of the above, please contact us at
pH electrode slope out of
range
(<85% or >110%)
The calibration reminder is
triggered. I
t’s t
ime to perform
a new pH calibration
Perform pH calibration or cancel calibration reminder in
ZenTest settings.
