Clean EC probe

Every month (weekly recommended) you should check the EC calibration. Remove shroud from end of probe. Clean the face of the probe, use a little kitchen liquid scouring cleaner such as “Jif" or "SoftScrub” on a clean “Scotchbrite” nylon scouring pad. Alternatively, use 600 grit wet-and-dry paper with the cleanser. Use a circular motion to scour the face of the probe and then rinse well in running water. Do not touch the face of the probe but shake off any residual water..

Replace the shroud and check calibration.

Calibrating the EC probe

After cleaning and rinsing the probe, shake vigorously to remove any surplus water. Now place the probe in EC standard solution and allow the temperature compensation to take full effect by leaving for 5 minutes or more. Calibration solutions are usually 2.76mS/cm referenced to 25oC but any calibration solution may be used.

The reading should settle to within 0.1 EC (1 CF or 5ppm) of the value stated on the bottle. If not then navigate to the EC calibration screen on the controller (not available on IntelliGrow) and press the up/down arrows until the reading exactly matches the value printed on the bottle. Note that calibration solutions are easily contaminated or changed by evaporation and should be replaced with fresh solutions every 3 months or more frequently if high accuracy is required.

Cleaning the pH electrode

The pH electrode is supplied with a protective cap or cover over its active end. Its purpose is to keep the glass bulb moist during storage and transit. This cover must be removed before use.

The glass bulb at the end of the pH electrode should be shiny and clear. If not then it may be cleaned by brushing with a soft toothbrush or special cleaning tool together with a little liquid scourer such as Jif or Soft Scrub. Do this very carefully as the glass bulb is extremely delicate. Rinse thoroughly with clean water.

Calibrating the pH electrode

Every week you should check the pH calibration. To do this place the probe in the pH7 buffer solution and allow to stand for 10 minutes. The reading should be 7.0 +/- 0.1 pH. If not then navigate to the pH 7 calibration screen and use the up/down arrows to correct the displayed reading. When correct, press save.

Next rinse the probe in fresh water and shake off excess water. Now place in the pH 4 buffer solution and allow to stand for 10 minutes. The reading should be 4.0 +/-0.1. If not navigate to the pH 4 calibration screen and use the up/down arrows to correct. Now press save to store the calibration.

IMPORTANT: The pH 7 calibration MUST be carried out before the pH 4 calibration.

pH electrodes last for between 6 months and two years. As soon as the electrode shows signs of drifting or slow response it should be renewed. For storage, the tip of the pH probe must always be kept wet, if they dry out, they will not work.

Peristaltic pump maintenance

These require very little maintenance other than occasional greasing of the rubber tubes (using special rubber grease from the manufacturer). The grease may be applied via the two greasing access points in the clear plastic pump covers. When the tubes become flattened they should be replaced.

Hint: it is sometimes possible to extend the life of the tube by sliding the tube around a little so that a new section of tube is exposed to the rollers. To do this, loosen the two screws in the front cover, slide tube and then retighten. Finally, add extra grease via the two greasing points in the front cover.

Solenoid valves

These need very little maintenance but if the flow rates of the A and B solutions becomes unequal the valves can easily be opened up for inspection and cleaning. If a valve stops working completely there is a possibility that the solenoid coil has become defective. The coils can be replaced.

General maintenance

Frequently inspect your system for leaks and repair these as soon as possible. Water dripping onto solenoids or pumps will soon cause them to fail. Ensure the controller, pump unit and solenoids are kept clean and shielded from all water splashes and vapours.

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