11.
Wait at least 2 hours for the sensor to stabilise
then recalibrate the dissolved oxygen
readings. This step is vital as the oxygen inside the sensor needs to be fully used before a
reading can be taken.
Dissolved Oxygen Stirrer Maintenance
The Stirrer for the dissolved oxygen sensor is a magnetically operated paddle which oscillates and
forces water past the sensor membrane. This stirrer may occasionally become clogged, particularly
if the water you are testing contains a large amount of magnetic particles. To remove the stirrer
paddle for cleaning, proceed as follows:
1.
Lift the wire clip off the post and push to the opposite side.
2.
Again lift the wire clip and rotate the paddle towards you so the clip may pass by. A small
black spacer will be dislodged and will need to be retained for reassembly.
3.
Pull the wire clip out. As this happens the stirrer and the opposite small black spacer will
come free.
4.
Clean the paddle and replace it in the reverse order.
pH/ORP Sensor Maintenance
Before use:
Always remember to remove the protector cap (cream in colour).
Electrochemical sensors change over time so calibration before field use will provide the
best accuracy.
After use:
Always rinse the probe and sensors of dirt, debris and sample liquid.
Replace protector cap (cream in colour) filled with a bit of ph probe keeper.
Standard non‐refillable sensor:
This sensors requires maintenance if there is a build up of
contamination on the glass membrane. A clean damp paper towel carefully wiped over the glass
will clean this sensors glass membrane. If the electrolyte becomes contaminated or depleted of
electrolyte the sensor will require replacement.
Optional refillable:
This optional sensor type has a refillable secondary junction. Also as the
electrolyte has a higher flow rate it requires regular electrolyte top up and calibration. By refilling
the electrolyte from the bottom this will displace the old electrolyte which will help slow
contamination from occurring.
Warning: Abrasive damage (including scratches) to the pH glass will reduce the sensor
performance.
The above maintenance is recommended prior to calibration. Follow a 2 point calibration
procedure for your water quality analyser. In some clean circumstances it is feasible to calibrate
without maintenance. A prolonged period of no maintenance will affect the reference and may
cause the centre offset to drift – meaning mid values may read high or low.
Storing
Do not store pH sensor in water as it will deplete the ions.
Do not let the pH sensor dry up.
Always rinse of contaminates and store clean.