Trouble Reason How to x
Cannot calibrate
Incorrect calibration order
Power on the tester, calibrate pH7 rst, then pH4. After pH4 is
calibrated, if you want to calibrate pH7 again, you need to reboot
the tester.
Poor quality standard
solutions
Replace with fresh and clean standard calibration solutions made
by legitimate manufacturers.
Contaminated probe Clean the probe with Apera's cleaning solution or detergent
water.
Aged prode Replace the probe.
Dried-out probe Soak the probe in the 3M KCL soaking solution for at least 1 hour.
Probe is not fully
submerged in the solution
Make sure the probe is fully immersed in the solution at least 1
inch deep.
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 probe with Apera's cleaning solution or detergent
water.
Clogged junction Clean the probe with Apera's cleaning solution, then soak in 3M
KCL soaking solution overnight.
Aged probe Replace the probe.
Testing pH of low ionic
strength solutions like tap
water, drinking water, RO
water, distilled water
Be patient, wait for 1-5 minutes to reach a fully stabilized reading.
If still not stabilizing, add 3M KCL soaking solution to your test
water at 1:1000 ratio(e.g. 1ml to 1000ml or 1 teaspoon to 1 gallon)
Display similar
readings in any
solutions or
always display 7.0
pH
Broken probe
If you don't nd any visible damage of the probe and it's within
the 1-year probe warranty, contact your point of purchase for
warranty fulllment;
If there is visible damage or the probe is aged, replace the probe.
Reading keeps
jumping
Probe is not fully
submerged in the solution
Make sure the probe is fully immersed in the solution at least 1
inch deep.
Air bubbles around the
sensor Make a quick stir in the solution to remove air bubbles.
Probe is not properly
connected or the pin
connector is broken.
Check the probe's connector, make sure it's not broken and is
connected. Align the probe and instrument correctly before
plugging in. Never force it.
Ensure tha the probe connector is not exposed in 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 probe with cleaning solution, the soak it in 3M KCL
soaking solution overnight
Comparison with other
testers, test strips, or drop
tests
To compare with other testers, make sure to calibration at the
same pH7 standard, the test pH4. Whichever gives more accurate
reading is the more accurate one.
Test strips or drop tests' accuracy is not comparable to pH meters'.
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