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Section 9 Troubleshooting
Keep the probe clean and in the recommended storage solution when not in use for the best
accuracy, stabilization time and life of the probe.
Problem
Decreased probe performance
causes slow stabilization and
prevents accurate calibrations
or measurements.
Sample properties cause slow
stabilization or inaccurate
measurements.
Procedure problem causes
slow stabilization and prevents
accurate calibrations or
measurements.
Section 10 Consumables
Note: Product and Article numbers may vary for some selling regions. Contact the appropriate distributor or refer to
the company website for contact information.
Description
Hach pH electrode storage solution
3 M KCl solution
2
Larger quantities are available for some items.
3
Larger quantities are available.
Possible cause
The glass sensor is dirty.
The glass sensor has become
dry.
The calibration slope of the
probe has changed.
The sample absorbs carbon
dioxide (CO
) from the air,
2
which causes the pH value to
slowly decrease in low ionic
strength (LIS) or high purity
samples.
The sample temperature is
low, or there is a large
temperature difference
between samples.
The probe is not conditioned
to the sample.
Air bubbles are around or
below the probe tip.
The electrical connection
through the reference junction
is not sufficient.
The stir speed is too slow or
too fast.
An incorrect buffer solution
was used or the buffer solution
has contamination.
Solution
Clean and condition the probe.
Refer to
Clean the probe
on page 9.
Clean and condition the probe.
Refer to
Maintenance
Increase the accepted slope limit
settings if possible, or contact
technical support.
Use the LIS chamber for
LIS/high purity samples to
prevent CO
absorption.
2
Increase the sample temperature
or adjust the temperature of
different samples to be the same
(within 2 °C (3.6 °F)).
Soak the probe in the sample
before sample measurements.
Refer to
Preparation for use
on page 5.
Carefully tap or shake the probe
to remove air bubbles.
Shake the probe in the solution
from side to side to refresh the
reference junction.
Try a different stir speed.
Use the specified buffer solutions
of good quality.
2
Quantity
Item no.
500 mL
2756549
3
50 mL
2756559
on page 9.
English 11
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