Aanderaa 4330 Operating Manual page 79

After cleaning the sensor it should be rinsed well in clean tap water before storing or reuse.
Do not use any organic solvents such as: Acetone, Chloroform and Toluene since these and others will damage the foil.
MM 2
Q: My foil has been damaged so that I can see scratches in the black protective layer and some blue light is coming out when measuring.
Do I need to change the foil?
A: No, normally not.
Even if quite heavily damaged the foil continues to work, in most cases. Caution should however be taken for transparent (fast response foils) and foils with
a damaged black layer to keep them out of sunlight that could bleach the sensing layer.
As long as enough of the fluorophore remains on the foil the sensor will measure correctly.
If heavily damaged it is however recommended to recalibrate the sensor (with a standard two point calibration, see Operating Manual or OxyView software).
If the sensor behaves normally when placed in an air-bubbled water solution (showing around 100 % saturation) the foil should be ok.
If the foil is not ok the sensor will return values that are illogical to what should be expected.
Then the foil needs to be exchanged, new calibration constants entered and a new two point calibration performed.
Remember that the Optode sensors can also be operated with transparent foils so the black protective layer is not essential.
If using a transparent foil it should then be noted that blue light will be spread out into the water.
This might induce primary production if measuring at a frequent time interval without moving the sensor.
MM 3
Q: I have an old RCM 7/RCM 8, can I mount the Optode and log it with this instrument?
A: No, the sensor does not fit physically on the top plate.
Neither will the RCM 7/8 be able to read the standard SR10 signal.
Response Time and Performance Checks
RTPC 1
Q: Why is the response time of the sensor slow?
A: It is slow because of two reasons.
First, the foil is covered with an opaque optical isolation layer to make it more rugged.
The optical isolation slows down the time it takes for oxygen to equilibrate within the foil.
Second, the response time of the temperature sensor, needed to compensate the optical readings, is also a limiting factor. In most long term applications
page 79 of 93
TD 269 OPERATING MANUAL
OXYGEN OPTODE 4330, 4831, 4835
June 2017