Sondes
Section
2
YSI Incorporated
Drinking Water Monitoring Systems Operations Manual
2-98
NOTE:
If this procedure is unsuccessful, or if probe performance is impaired, it may be necessary to
return the probe to an authorized dealer service center See
Section 8, Warranty and Service
Information
for contact information.
The temperature portion of the probe requires no maintenance.
6561/6561FG pH AND 6565/6565FG/6566/COMBINATION pH-ORP PROBES
Cleaning is required whenever deposits or contaminants appear on the glass and/or platinum surfaces of
these probes or when the response of the probe becomes slow.
Remove the probe from the sonde. Initially, simply use clean water and a soft clean cloth, lens cleaning
tissue, or cotton swab to remove all foreign material from the glass bulb (6561 and 6565) and platinum
button (6561). Then use a moistened cotton swab to carefully remove any material that may be blocking
the reference electrode junction of the sensor.
CAUTION:
When using a cotton swab with the 6561 or 6565, be careful NOT to wedge the swab tip
between the guard and the glass sensor. If necessary, remove cotton from the swab tip, so that the cotton
can reach all parts of the sensor tip without stress. You can also use a pipe cleaner for this operation if
more convenient.
If good pH and/or ORP response is not restored by the above procedure, perform the following additional
procedure:
1.
Soak the probe for 10-15 minutes in clean water containing a few drops of commercial dishwashing
liquid.
2.
GENTLY clean the glass bulb and platinum button by rubbing with a cotton swab soaked in the
cleaning solution.
3.
Rinse the probe in clean water, wipe with a cotton swab saturated with clean water, and then rerinse
with clean water.
If good pH and/or ORP response is still not restored by the above procedure, perform the following
additional procedure:
1.
Soak the probe for 30-60 minutes in one molar (1 M) hydrochloric acid (HCl). This reagent can be
purchased from most distributors. Be sure to follow the safety instructions included with the acid.
2.
Rinse the probe in clean water, wipe with a cotton swab saturated with clean water, and then rerinse
with clean water. To be certain that all traces of the acid are removed from the probe crevices, soak
the probe in clean water for about an hour with occasional stirring.
If biological contamination of the reference junction is suspected or if good response is not restored by the
above procedures, perform the following additional cleaning step:
1.
Soak the probe for approximately 1 hour in a 1 to 1 dilution of commercially-available chlorine bleach.
2.
Rinse the probe with clean water and then soak for at least 1 hour in clean water with occasional
stirring to remove residual bleach from the junction. (If possible, soak the probe for period of time
longer than 1 hour in order to be certain that all traces of chlorine bleach are removed.) Then rerinse
the probe with clean water and retest.
