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Galvanic Sensors
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 the 5912 (1 mil Teflon), less rapid with 5913 (1.25 mil PE), and least rapid
with 5914 (2 mil PE).
At the time the membrane cap is changed, YSI recommends that you rinse the anode (silver shaft of the sensor) with purified water
and wipe with a clean paper towel. If white deposits are evident on the anode after cleaning, YSI recommends that you remove
this material by sanding the anode with the sandpaper disk enclosed in your membrane kit. Follow the “Mechanical Cleaning”
instructions under the Polarographic Silver Anode section.
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.
IMPORTANT:
Be sure to: (1) Use only the fine sanding disks provided and (2) Sand as mentioned in the above
procedures. Not adhering to either of these instructions can damage the electrodes.
WARNING:
DO NOT PERFORM THE POLAROGRAPHIC CHEMICAL CLEANING ON A GALVANIC SENSOR. If this
procedure is unsuccessful, as indicated by improper electrode performance, contact YSI Technical Support or the
Authorized dealer where you purchased the instrument
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