wtw inoLab pH 720, Operating Manual, Page: 34 / 48

What to do if... pH 720
34
Buffer solutions:
– Incorrect buffer solutions – Change calibration
procedure
– Buffer solutions too old – Only use once.
Note the shelf life
– Buffer solutions depleted – Change solutions
Cause Remedy
pH electrode:
– Diaphragm contaminated – Clean diaphragm
– Membrane contaminated – Clean membrane
Sample:
– pH value not stable – Measure with air
excluded if necessary
– Temperature not stable – Adjust temperature if
necessary
Ele sample:
– Conductivity too low – Use suitable electrode
– Temperature too high – Use suitable electrode
– Organic liquids – Use suitable electrode
Cause Remedy
– Batteries almost depleted – Replace batteries
(see section
5.1 M
AINTENANCE
)
No stable
measured value
LoBat