YSI 5239 Dissolved Oxygen Probe - Manual (Page 14)

10
M AINTENANCE A ND T ROUBLESHOOTING
M EMBRANE C AP L IFE
If the probe is properly maintained, one membrane cap should
last two to four weeks depending on how often the probe is
used and the type of samples measured. Keep the probe in a
moist atmosphere as much as possible to avoid drying out the
electrolyte. Erratic readings will result from loose, wrinkled or
fouled membranes, or from bubbles larger than 1/8” in the
electrolyte solution. The following things are likely to cause
short membrane life:
1. The electrolyte has dried out because the membrane
cap was not tight or the probe was exposed to dry air
for a long time.
2. The membrane was not properly installed. For
instance, wrinkles have formed after membrane
installation.
3. The probe was not properly rinsed with water after a
field measurement, allowing mud or algae to attach to
the membrane.
4. The membrane was damaged by an object, such as
reeds or small sticks in the water.
5. The probe has struck a hard object and the sensor or
membrane has been damaged.