Hanna Instruments HI 3512 User Manual

Page 73

For refillable electrodes:

If the filling solution (electrolyte) is more than 2½ cm (1”) below the fill
hole, add

HI 7082 or HI 8082 3.5M KCl Electrolyte Solution for double

junction or

HI 7071 or HI 8071 3.5M KCl+AgCl Electrolyte Solution for

single junction electrodes.
For faster response, unscrew the fill hole screw during measurements.
For AmpHel

electrodes:

If the electrode does not respond to pH changes, the battery has run
down and the electrode should be replaced.

MEASUREMENT

Rinse the pH electrode tip with distilled or deionized water. Immerse the
tip 3 cm (1¾”) in the sample and stir gently for a few seconds.
For a faster response and to avoid cross-contamination of the samples,
rinse the electrode tip with a few drops of the solution to be tested, before
taking measurements.
See that the sleeve holes of the ORP probe are completly submersed.

STORAGE PROCEDURE

To minimize clogging and assure a quick response time, the glass bulb
and the junction of pH electrode should be kept moist and not allowed to
dry out.
Replace the solution in the protective cap with a few drops of

HI 70300

HI 80300 Storage Solution or, in its absence, Filling Solution

(

HI 7071 or HI 8071 for single junction and HI 7082 or HI 8082 for

double junction electrodes). Follow the Preparation Procedure on page
72 before taking measurements.

Note: NEVER STORE THE ELECTRODE IN DISTILLED OR DEIONIZED WATER.

PERIODIC MAINTENANCE

Inspect the electrode and the cable. The cable used for connection to the
instrument must be intact and there must be no points of broken
insulation on the cable or cracks on the electrode stem or bulb. Connectors
must be perfectly clean and dry. If any scratches or cracks are present,
replace the electrode. Rinse off any salt deposits with water.

pH Probe Maintenance

For refillable electrodes:

Refill the reference chamber with fresh electrolyte (

HI 7071 or HI 8071 for

single junction or

HI 7082 or HI 8082 for double junction electrodes).

Allow the electrode to stand upright for 1 hour.