Hach PHC725, User Manual

Page: 10 / 22

5.2 Calibration procedure
1. Go to the
calibrate menu.
Select the probe, if
applicable. The
display shows the
pH buffer solutions
to use for calibration.
2. Prepare or pour
the pH buffer
solutions in different
beakers.
3. Open the filling
hole.
4. Rinse the probe
with deionized water.
Dry the probe with a
lint-free cloth.
5. Put the probe in
the first pH buffer
solution. Make sure
that the sensor and
reference junction
are fully in the
solution. Do not put
the probe on the
bottom or sides of
the beaker.
6. Shake the probe
from side to side to
refresh the reference
junction and remove
air bubbles.
Note: Be careful to not
hit the beaker and
damage the probe.
7. Stir slowly, then
read the pH value of
the buffer solution.
The display shows
the temperature-
corrected pH value
when the reading is
stable.
8. Continue with
steps 4 through 7 for
the remaining
buffers or select
Done.
9. Save the
calibration.
8 English