YSI pHotoFlex pH Handheld Colorimeter - Manual (Page 83)

pHotoFlex
®
pH What to do if...
83 ba76123e01 02/2013
Measured value display
----
(calibration error)
No stable measured
value
Cause Remedy
Electrode:
– Diaphragm contaminated – Clean diaphragm
– Membrane contaminated – Clean membrane
– Moisture in the plug – Dry plug
– Not enough electrolyte – Top up electrolyte
– Electrode obsolete – Replace electrode
– Electrode broken – Replace electrode
– Socket damp – Dry socket
Calibration procedure:
– Incorrect solution temperature
(without temperature sensor)
– Set up correct temperature
– Incorrect buffer solutions – Select buffer solutions
suitable for the calibration
procedure
– Buffer solutions too old – Use only once.
Note the shelf life
Cause Remedy
pH electrode:
– Diaphragm contaminated – Clean diaphragm
– Membrane contaminated – Clean membrane
Test sample
– pH value not stable – Measure with air excluded if
necessary
– Temperature not stable – Temper if necessary
Electrode + test sample:
– Conductivity too low
(e.g. in ultrapure water)
– Use suitable electrode
– Temperature too high – Use suitable electrode
– Organic liquids – Use suitable electrode