11
10
pH ELECTRODE MAINTENANCE
Preparation
Remove the electrode protective cap. Do not be alarmed if any salt deposits are
present: this is normal with electrodes and they will disappear when rinsed with
water.
During transport tiny bubbles of air may have formed inside the glass bulb. The
electrode cannot function properly under these conditions. These bubbles can be
removed by "shaking down" the electrode as you would do with a glass
thermometer.
Sensitive bulb
To avoid clogging problems and ensure a fast response, the bulb must be kept
moist at any time. Store the electrode with few drops of
HI 70300
storage
solution in the protective cap. NEVER USE DISTILLED OR DEIONIZED WATER FOR
STORING PURPOSES.
Periodic maintenance
Inspect electrode and cable. The cable used for the connection to the meter must
be intact and there must be no points of broken insulation. The connector must
be perfectly clean and dry. If any scratches or cracks are present, replace the
electrode.
Refilling the electrode
ALWAYS VERIFY THE ELECTROLYTE LEVEL.
If the electrolyte level is more than 2 cm below
the refilling hole, unscrew and remove the refill-
ing hole cap.
Add the 3.5M KCl electrolyte solution (
HI 7082
)
by using the supplied syringe. Tighten back the
cap. Wait at least 1 hour before using the
electrode.
pH VALUES AT VARIOUS TEMPERATURES
pH readings are strongly affected by temperature. The calibration buffer
solutions are affected by temperature changes to a lesser degree than normal
solutions.
For manual temperature calibration please refer to the following chart.
Note:
To prevent damage to the electrode, remove the pH electrode from the
sample before turning the meter off. With the meter OFF, detach the
electrode from the meter and immerse it in the storage solution.
TEMP pH VALUES
°C
°F
3.00
6.86
7.01
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
32
41
50
59
68
77
86
95
104
113
122
131
140
149
158
3.07
3.05
3.03
3.02
3.00
3.00
3.00
3.00
2.99
2.99
2.99
2.99
2.99
2.99
3.00
6.98
6.95
6.92
6.90
6.88
6.86
6.85
6.84
6.84
6.83
6.83
6.84
6.84
6.85
6.85
7.13
7.10
7.07
7.04
7.03
7.01
7.00
6.99
6.98
6.98
6.98
6.98
6.98
6.99
6.99
