Aquameter
™
Series Instruction Manual
10401-00188 Rev M
2. Unscrew the DO Membrane cap from the end of the DO/EC electrode by rotating it
anti-clockwise.
3. Gently brush away any scaly grey deposits from the coiled wire section of the
electrode with a soft toothbrush, taking care not to damage the coil in the process.
4. After removing the deposits, rinse the electrode with DO Electrode Filling Solution.
5. Rinse a new DO Membrane Cap with DO Electrode Filling Solution then tap it out so
that it is completely empty.
6. Using the DO Electrode Filling Solution dropper bottle, half fill the DO Membrane
Cap. Gently tap the cap to ensure any trapped air bubbles are released.
7. Holding the Probe so that the DO electrode is facing downwards,
slowly
screw the
half-filled DO Membrane Cap back onto the DO electrode then tighten the cap.
Do
not over-tighten
. Finger tight is fine. Some solution will overflow. This is normal.
8. Wash the DO/EC electrode with fresh water then replace the lower Probe sleeve.
9. Wait at least six hours (preferably over-night) to allow any oxygen dissolved in the
filling solution to be consumed.
10. Carry out both Zero point and 100% point DO calibration as described earlier.
Do not re-install a Galvanic DO Membrane Cap once it has been fully tightened.
The
membrane will be stretched and will not seal properly over the silver cathode a second
time. If the membrane does not create a proper seal over the silver cathode, the DO sensor
will not operate correctly and any readings given will be erroneous.
14.8. Replacing the Optical DO Cap (AP-900 & AP-1000 only)
The Optical DO Cap contains a lens, which is coated with an oxygen sensitive
luminophore, which is in turn coated with a black rubber compound that provides optical
isolation but is permeable to oxygen. Oxygen molecules pass through the rubber into the
luminophore.
Never touch the black rubber end of the DO electrode as the oils in your skin can
block the pores in the rubber coating and stop it from working correctly.
The luminophore within the DO Cap will need replacing ever 1 – 2 years, as it is a
consumable item. Since the luminophore is an integral part of the DO Cap, the entire DO
Cap is replaced. An Optical DO Cap can last up to two years dependent upon the amount
of use it gets. See
in Appendix 1 for further details.
Caution: The inside of the Optical DO Cap is very sensitive to light and can be ruined
(bleached) if it is exposed to bright light for any length of time. Never remove the Optical
DO Cap from the Probe unless you intend to replace it with a new one. When replacing an
Optical DO Cap, do so under subdued light.
To replace the Optical DO Cap, follow these simple steps.
1. Remove the Probe sleeve.
2. Unscrew the Optical DO Cap from the end of the DO/EC electrode by rotating it anti-
clockwise.
Do not touch the exposed optical components.
3. Apply a light smear of silicone grease to the thread and O ring.
4. Remove the new Optical DO Cap from its light-proof bag and quickly screw it onto
the end of the DO/EC electrode.
5. Carry out both Zero point and 100% point DO calibration as described earlier.
Please Note: It is essential when replacing the Optical DO Cap to calibrate the Zero
point BEFORE calibrating the 100% point.
© 2011 Aquaread Ltd.
www.aquaread.co.uk
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