Hach PHC735, User Manual

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5. Put the probe in
the pH buffer
solution with the
sensor and
reference junction
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 gently, then
read the pH value of
the buffer solution.
The meter accepts
or rejects the result.
Section 8 Maintenance
Regular maintenance is necessary for the best accuracy, stabilization time and life of the probe.
Keep the probe in the recommended storage solution between measurements.
8.1 Clean the probe
Clean the probe regularly to remove contamination and to keep the reference junction open.
Symptoms of contamination:
• Incorrect or irregular readings
• Slow stabilization times
• Calibration errors
• Sample material stays on the probe
1. Rinse the probe with deionized water. Use warm (35–45 °C (95–113 °F)) deionized water to
remove storage solution that dries on the probe. Dry the probe body with a lint-free cloth.
2. Soak the glass bulb and reference junction in the applicable cleaning solution for the specified
time. Refer to
Table 1 and Consumables on page 17.
3. Rinse or soak the probe for 1 minute in deionized water. Dry the probe body with a lint-free cloth.
4. Soak the probe in pH 4 buffer for 20 minutes.
5. Rinse the probe with deionized water. Dry the probe body with a lint-free cloth.
Table 1 Cleaning solution
Contamination Cleaning solution Active component Soak time
General
contamination Electrode cleaning solution
for regular maintenance KATHON
™
CG,
DECONEX ® 11
12–16 hours
Minerals Electrode cleaning solution
for minerals/inorganic
contamination Phosphoric acid
(~10%) 10–15 minutes
Fats, grease and oils Electrode cleaning solution
for fats, oils and grease
contamination KATHON
™
CG,
TRITON ® X
2 hours maximum
English 11