YSI Pro20 - Manual (Page 35)

After completing the sanding procedure, repeatedly rinse the electrode with clean
water and wipe with lens cleaning tissue to remove any grit left by the sanding disc.
Thoroughly rinse the entire tip of the sensor with distilled or deionized water and
install a new membrane.
IMPORTANT : Be sure to: (1) Use only the fine sanding discs
provided and (2) Sand as mentioned in the above procedures. Not
adhering to either of these instructions can damage the electrodes.
If this procedure is unsuccessful, as indicated by improper sensor performance,
contact YSI Technical Support or the Authorized dealer where you purchased the
instrument.
Galvanic Sensors – Model # 605202
We recommend that the Sodium Chloride (NaCl) solution and the membrane cap
be changed at least once every 60 days during regular use. In addition, the NaCl
solution and membrane should be changed if (a) bubbles are visible under the
membrane; (b) significant deposits of dried electrolyte are visible around the
membrane; and (c) if the sensor shows unstable readings or other sensor-related
symptoms.
The Galvanic dissolved oxygen sensor is continuously reducing oxygen even when
the display of the instrument is not active. This factor allows the sensor to be used
with no warm-up period as soon as the instrument is powered on (instant on DO).
However, because the sensor is “on” all the time, some solid from the oxidation of
the zinc anode will form in the electrolyte within 1-2 weeks of activation. Small
amounts of the solid will generally cause no performance problems, but excessive
amounts may result in jumpy dissolved oxygen readings. The rate of solid
formation is dependent on the type of membrane installed. The formation of
solids based on membrane type typically form more rapidly with 5913 (1.25 mil
PE), and less rapid with 5914 (2 mil PE).
The Galvanic DO sensor solution will appear milky white after use
but will NOT affect the accuracy of the sensor unless there is
excessive build up. The color change is acceptable and normal as
long as DO readings remain stable.
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