Sper Scientific 860031 pH - mV Bench-Top Meter - Manual (Page 54)

54
MAINTENANCE
the probe should be rinsed and stored in the soaker
bottle filled with the soaking solution.
ORP Probe Cleaning
A contaminated sensing element can result in a slow
response and/or inaccurate reading.
 If the contamination is mineral matter, put the sensing
element in a 0.1 N HCl solution for 10 minutes. Rinse in
distilled water.
 If the contamination is oil or grease, clean with a mild
detergent. Rinse in distilled water.
Upon completion of either cleaning method, immerse the
probe in a saturated buffer solution with pH 4.01 for 15
minutes and rinse with distilled water. After cleaning, soak
the probe in solution for at least 8 hours.
Probe Performance
The sensing element of an ORP probe is made of a high
purity metal. Soaking the sensing element in a solution for
a long period of time may cause slow response time and
inaccurate readings. An oxidation reduction coating may
have formed on the surface of the sensing element.
Resolve by cleaning the element.
When measuring a solution with a low concentration of
oxidation reduction matter and slow ion exchange rate, a
slow response time and inaccurate readings may occur.
Under these conditions, it may take 8-24 hours to obtain an
accurate reading.