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Thread the membrane cap onto the sensor. It is
normal for a small amount of electrolyte to overflow.
Replace the sensor guard.
Polarographic Sensors – Model # 605203
The KCl (potassium chloride) solution and the membrane cap should
be changed at least once every 30 days during regular use. In addition,
the KCl solution and membrane should be changed if (a) bubbles
are visible under the membrane; (b) significant deposits of dried
electrolyte are visible on the membrane; and (c) if the sensor shows
unstable readings or other sensor-related symptoms.
Figure 11, DO sensor with membrane removed.
During membrane changes, examine the gold cathode at the tip of
the sensor and the silver anode along the shaft of the sensor. If either
the silver anode is black in color or the gold cathode is dull, the sensor
may
need resurfaced using the fine sanding disks included in the
membrane kit. Do not sand the electrode every membrane change as
this is not
routine
maintenance. In fact, visually, the anode may appear
tarnished and operate just fine. YSI recommends using the 400 grit
wet/dry sanding disks after a membrane change if the sensor has
difficulty stabilizing or calibrating.
