YSI 58 - Manual (Page 22)

readings or evidence of membrane damage occurs, you should replace the membrane cap and the
probe solution.
3. If the membrane is coated with oxygen consuming (e.g. bacteria) or oxygen evolving organisms
(e.g. algae), erroneous readings may occur.
4. Chlorine, sulfur dioxide, nitric oxide, and nitrous oxide can affect readings by behaving like
oxygen at the probe. If you suspect erroneous readings, it may be necessary to determine if these
gases are the cause.
5. Avoid any environment that contains substances that may attack the probe materials. Some of
these substances are concentrated acids, caustics, and strong solvents. The probe materials that
come in contact with the sample include FEP Teflon, stainless steel, epoxy, polyetherimide and
the polyurethane cable covering.
6. Do not allow the probe to strike hard objects. The membrane or sensor inside may be damaged.
5.3.1 5905 AND 5239 PROBE CARE
ELECTRODE CLEANING
The 5905 and 5239 probes should be cleaned only when erratic readings occur or after about every
500 hours of use (two months). Each cleaning removes material, so excessive cleaning should be
avoided.
GOLD CATHODE
For correct probe operation, the gold cathode must be textured properly. It can become tarnished or
plated with silver after extended use. The gold cathode can be cleaned by using the adhesive backed
sanding disc provided in the 5906 Membrane Kit. Stick the disc to a small flat object, like a bottle
cap, then sand the gold with a twisting motion about 3 times or until all silver deposits are removed
and the gold appears to have a matte finish. If the cathode remains tarnished, return the probe for
service.
Cathode
(Gold)
Temperature
Sensor
Anode
(Silver)
Figure 8
SILVER ANODE
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