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Aquaprobe
®
AP-5000 Instruction Manual
10401-00906 Rev M
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.
The AP-5000 is provided with a two part calibration cup. The probe is designed to be
calibrated in these cups
with the Probe Sleeve and Sleeve End Cap fitted.
The Probe sleeve and End Cap form an integral, working part of the Probe’s optical
and EC measurement system, and MUST be fitted during calibration and
measurement for correct operation.
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
Electrodes 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 and the pH7.00 point 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 any optical electrodes
you may have fitted. To use RapidCal:
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®
Ltd.
www.aquaread.com
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