Hydrion 10 - Selecting a Calibration Set; One-Point Calibration

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2.3.2 Selecting a Calibration Set
Open the drop-down menu under [Calibrate], and click on [Selecting a calibration set]. Another drop-down menu will
appear, with three predefined calibration sets: pH 9_7_4, pH 7_4 and Standard. Beneath these will be listed any
additional, user-defined calibration sets. These user-defined sets can be deleted.
Select the desired calibration set and activate it by clicking inside the table. This will cause all the drop-down menus to
disappear. The selected calibration set is now activated, and its name will appear in the Project window.
2.3.3 One-Point Calibration
Once the desired calibration set is selected, click again on [Calibrate] in the menu bar, choose [one-point calibration]
from the drop-down menu and click on [Start]. The one point calibration can also be started by clicking on [one point
calibration] in the project window.
Place the Sensor-unit in the correct calibration fluid and click on [OK] to start the calibration.
If, by any chance, the wrong calibration fluid is used, the program will automatically notice after one minute and will
interrupt the procedure with the comment: “Wrong Calibration fluid”.
The one-point calibration has to be repeated every two hours. Therefore, if you start a new measurement session on a
new day, you must always begin with a one-point calibration.
pH Calibration
A pH one-point calibration has to be carried out once every week. Whenever there is a need for a one-point calibration,
the Hydrion10 Program will warn you by graying-out the little windows for pH and HCO3 measurement results. After a
one-point pH calibration, the Sensor-Unit should be rinsed and placed in (old) standard fluid 2 for at least 15 minutes.
Calibration Interval
The two hour interval for the one-point calibration for all sensors, except the pH, and the one week interval for the one-
point calibration for the pH have been set as defaults in the program. If necessary, these settings can be changed by a
service engineer, but not by the user. Since we now use a much better reference electrode, recalibration every two hours
may not be required anymore.
Control Measurements
It is advisable to perform a control measurement on a standard solution with a known composition. For the standard
calibration set, we recommend using Evian bottled water or a comparable mineral water with a stable composition. This
control measurement should be performed after every one-point calibration and once every hour during measurement
sessions.
When results differ more than 10% from the actual values, you must repeat the one-point calibration.