10.2 Setting the switching values
The “Hys” function enables the switching values (hysteresis) to be set at which the pH-Controller
is to activate and deactivate the supply of CO
2
.
Example 1: Switching values 0.1 - pH setting 6,8
The pH-Controller switches on the CO
2
supply when the pH value in the aquarium rises above 6.9
and off when it drops below 6.7.
Example 2: Switching values 0.01 - pH setting 6.8
The pH-Controller on the CO
2
supply when the pH value in the aquarium rises above 6.85 and off
when it drops below 6.75.
• Press “Hys” key: The currently set value appears on the display.
• Set the desired value with “+” and “-”.
• When the keys remain unused for 3 sec., this value will be adopted.
The pH-Controller controls the pH value accordingly.
Possible values: 0.01 - 0.05 - 0.1 - 0.15 - 0.2. Factory setting: 0.1 (recommended).
11 Automatic calibration reminder
The yellow LED "Calibration reminder" reminds the user automatically every 4 weeks that the
electrode is due for recalibration (the pH7 LED lights up at the same time). With regard to the
calibration procedure, see Point 11.
The calibration reminder does not affect the normal measuring and control functions of the pH
controller.
12 Supplementary calibration
Additional calibration of the electrode is possible at any time, irrespective of whether the cali-
bration reminder is active:
• Press "pH 7". The "pH 7" LED and the "Calibration reminder" LED light up.
• If key "pH 7" is pressed again within 1 minute, the controller will switch from normal control mode to
calibration mode. The "pH" LED will go off and the connected solenoid valve will be switched off.
• Rinse electrode briefly in distilled water.
• Place electrode in pH 7 calibrating solution.
• Wait approx. 1 minute for the electrode to adapt to the calibrating solution. Adaptation is complete
when the displayed measurement value no longer alters.
• Press "pH 7". The yellow LED flashes, the devices now calibrates automatically at pH 7, the display
shows "E 7".
• Now calibrate as described under Point 5.3 Calibration procedure.
Additional calibration of the electrode should be carried out in particular 1 week after starting up
the pH controller for the first time or connecting a new pH electrode.
13 Warnings
13.1 Flashing display
The display will flash if the pH value in the aquarium deviates from the set value by more than
+ 0.5 or - 0.5. In such cases, the system should be checked immediately:
• Is there any CO
2
left in the cylinder?
• Is the number of bubbles per minute set correctly?
• If pH value is too high: Is the number of bubbles per minute perhaps too low?
• If pH value is too low: Is the number of bubbles per minute perhaps too high?
• Is the solenoid valve working?
• Is the pH-electrode fitted correctly in the aquarium?
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17
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