Aquaprobe
®
AP-700, AP-800 & AP-2000 Instruction Manual
10401-00870 Rev R
10. RapidCal Calibration Method
10.1. About Calibration
Calibration is a very important part of successful water quality measurement and should be
carried out regularly as detailed in each separate section of this manual. A great deal of
development work has been put into simplifying and automating the calibration procedures
in the Aquameter
®
in order to allow normal field operatives (as opposed to trained lab
technicians) to achieve quick and accurate results.
As a general rule, pH and EC should be calibrated as close to 25ºC as possible. Optical
electrodes should be calibrated as close to their deployment temperature as possible.
In order to standardise calibration techniques, Aquaread
®
provide plastic calibration bottles
into which the Aquaprobe
®
can be directly inserted. The Aquaprobe
®
is designed to be
calibrated in these calibration bottles
with the Probe Sleeve and Sleeve End Cap fitted.
The Probe Sleeve and Sleeve End Cap form an integral, working part of the Probe’s
measurement system, and MUST be fitted during calibration and measurement for
correct operation.
See section
2.3 Important Information about the Probe Sleeve &
Sleeve End Cap
for further details.
10.2. Special Notes Concerning ISE Electrodes
The high ionic concentration of pH calibration solutions
(buffers), including RapidCal, can cause significant
offsets in ISE electrodes.
These offsets are temporary, but best avoided because
they can cause significant errors during both calibration
and normal operation.
For this reason all ISE electrodes are supplied with a red
rubber sealing cap.
The caps should be fitted to all
ISE Electrode when using RapidCal
in order to protect
the ISE electrodes from the effects of the buffer solution.
At all other times, the ISE electrodes should be left uncovered.
10.3. Using RapidCal
RapidCal calibrates EC at 2570µS/cm, the pH7.00 point and the zero point of all optical
electrodes (except Turbidity) simultaneously. Ideally, this procedure should be carried out
at the beginning of each day the Probe is to be used. In addition, you should check the DO
100% calibration point and zero the Turbidity electrode if fitted. To use RapidCal:
1. Remove the lid from a fresh bottle of RapidCal solution, remove the storage cap
from the pH electrode if fitted, wash the Probe in distilled water, ensure the Probe
Sleeve and End Cap are fitted, then drop the Probe into the RapidCal solution. Bang
the Probe against the bottom of the bottle several times in order to remove any air
bubbles that may be clinging to the electrodes.
© 2017 Aquaread
®
Ltd.
www.aquaread.com
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