Aquaprobe
®
AP-7000 Instruction Manual
10401-00894 Rev M
26. Appendix 7. Troubleshooting Turbidity
The Aquaread
®
Turbidity electrode is incredibly sensitive and is capable of measuring
between 0 and 3000NTU with an internal resolution of greater than 0.1NTU. This means
that the electrode is able to detect changes in turbidity that are less than 0.003% of the full
range.
It follows, therefore, that in order to provide stable, repeatable readings, especially at very
low levels, the environment in which the measurements are made must be completely
stable and repeatable.
For this reason, all Aquaprobes are
constructed with a matt black
aluminium sleeve and end cap that
enclose the sensing electrodes and
provide a constant condition, non
reflective measurement chamber.
This is essential for the correct
calibration and operation of the
turbidity electrode.
A diagram of the AP-7000
Aquaprobe’s measurement
chamber is shown here.
In order to obtain consistent
results, the measurement chamber
created within the Aquaprobe
®
must
remain physically constant during
both calibration and measurement.
If the turbidity electrode is calibrated
under one set of conditions, then used
to measure under another set of
conditions, the readings will naturally
be erroneous, especially at low
concentrations.
A perfect example of this is calibrating with the end cap removed then measuring with the
end cap fitted (or vice-versa). By changing the physical characteristics of the measurement
chamber, you also change the calibration and response of the electrode.
26.1. Lens and Sleeve Maintenance
On a daily basis, the lenses on the electrode should be wiped over with a soft damp cloth.
Similarly, the inside of the Probe Sleeve and Sleeve Cap should be kept clean and free
from any deposits that may cause stray reflections.
Never use an abrasive cleaner on the inside of the Probe sleeve or cap as they have
been treated with a non-reflective coating which can be easily damaged.
© 2017 Aquaread
®
Ltd.
www.aquaread.com
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