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15. Troubleshooting Guide
Trouble
Reason
How to fix
Cannot calibrate
Incorrect calibration order
When powered on, calibrate pH 7 first, then pH 4. After pH 4 is
calibrated, if you want to calibrate pH7 again, you need to power
off and restart the tester.
Bad standard solutions
Replace with a new reliable buffer solution.
Contaminated probe
Clean the electrode, it is best to use a cleaning solution.
Aged probe
Replace the probe.
Dried-out probe
Soak in the soaking solution overnight.
Probe is not fully submerged in
the solution
Make sure the electrode is immersed in the solution at least 3 cm.
Air bubbles around the sensor
Make a quick stir in the solution to remove air bubbles.
Reading is always
slowly changing,
won’t stabilize.
Contaminated probe
Clean the electrode, it is best to use a cleaning solution.
Clogged junction
Clean the electrode with cleaning solution, then soak it in 3M KCL
storage solution overnight.
Aged probe
Replace the probe.
Testing purified water like tap
water, drinking water and RO
water
Be patient, wait for 2-5 minutes to fully stabilize. If still not
stabilizing, add in 1ml of 3M KCL solution to 1000ml of test
solution.
Testing low ion concentration
solutions e.g. distilled water and
deionized water
Contact Apera for a specialized pH electrode suitable for low ion
concentration solutions.
Display similar
readings in any
solutions or
always display 7.0
pH
Broken probe
If you don’t find any visible damage of the electrode and it’s
within the 6-month electrode warranty, contact us for warranty
fulfillment;
If there is visible damage, replace the electrode.
Instrument defect
Contact us for warranty fulfillment
Reading keeps
jumping
Probe is not fully submerged in
the solution
Make sure the electrode is immersed into the solution for at least 1
inch.
Air bubbles around the sensor
shield
Make a quick stir in the solution to remove air bubbles.
Probe is not properly connected
or the connector is broken.
Check the electrode’s connector, make sure it’s not broken and is
correctly connected. Align the electrode and instrument correctly
before plugging in. Never force it.
Ensure that the electrode connector is not exposed to the air too
long.
Calibration is
successful, but
reading is not
accurate
Aged probe
Replace the probe.
Air bubbles around the sensor
Make a quick stir in the solution to remove air bubbles.
Clogged junction
Clean the electrode with cleaning solution, then soak it in 3M KCL
storage solution overnight
.
Comparison with other testers,
test strips, or drop tests
To compare with other testers, make sure to perform a 2-point
calibration for all testers in the same standards, then test a 3rd
point. Whichever gives more accurate reading in the 3rd point
standard is the most accurate one.
Test strips or drop tests’ accuracy is not comparable to pH meters’.
Calibration standards are not in
good condition
Make sure your calibration standards are fresh and clean, and
made by a legitimate scientific equipment manufacturer.
Your electrode is not suitable
for your test sample or testing
environment
Contact us to find the most appropriate electrode for your specific
application.
