Description

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.

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 the RapidCal Solution:

  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.
  2. When the Probe is inserted, ensure the level of the solution is at least up to the minimum insertion line scribed around the Probe sleeve. If the level is low, the EC electrodes will not be covered and EC will not calibrate properly. If the level is low, top up with fresh RapidCal solution.
  3. Switch the Aquameter on and wait until all readings are completely stable. The longer you can leave the probe to achieve thermal equilibrium before proceeding, the better.
  4. Ensure the temperature of the solution is between 5ºC and 40ºC (41ºF – 104ºF). The closer to 25ºC the better.
  5. Press the MENU key then select Calibration.
  6. Select RapidCal.

The meter will wait until all readings are stable, then it will send the RapidCal command to the Probe, where the calibration takes place. During calibration, the Calibrating screen is displayed and the progress counter counts up. If the calibration is successful, the counter will reach 100% and display will update. When calibration is complete, press OK then ESC to return to normal reading mode.

The RapidCal solution is available in a 250ml or 500ml bottle, or as a powder for dilution with De-Ionised water for 3L or 10L volumes.