Hach PHC281, User Manual

Page: 15 / 20

8.3 Replace the filling solution
If the filling solution becomes contaminated, replace the filling solution.
1. Tilt the probe and open the filling hole.
2. Use a plastic transfer pipet to remove the contaminated solution from the filling hole. Discard the
solution.
3. Rinse the inner probe three times with deionized water.
4. Rinse the inner probe three times with new filling solution.
5. Fill the probe with new filling solution. Refer to Fill the probe on page 12.
8.4 Soak procedure for dry probes
If the glass bulb becomes dry, complete the steps that follow to hydrate the probe.
1. Soak the probe tip in pH 4 and pH 7 buffer solutions for 5 minutes in each solution.
2. Rinse the probe with deionized water. Blot dry with a lint-free cloth.
3. Calibrate the probe.
8.5 Storage
N O T I C E
Probes can become permanently damaged if kept in a storage solution that is not specified by the
manufacturer. Use only the specified storage solution (2.44 M KCl).
Do not store the probe in deionized water or in samples of low ionic strength. For short-term storage,
the probe can stay in the sample for a maximum of 2 hours if the sample pH is not high. Close the
filling hole and put the soaker bottle that contains the storage solution on the probe when not in use.
Refer to
Figure 6 . Keep the probe in a vertical position with the sensor and reference junction below
the liquid level in the soaker bottle. Add storage solution to the soaker bottle if necessary.
Figure 6 Probe storage
English 13