Why is the circulation performance of my external filter reducing?
The output reduction of your external filter is most probably not a failure of your appliance.
This type of pump system is based on the synchronous motor principle. This means that the impeller rotates at 3000 rpm. synchronised with the frequency of the mains supply or it is idle.
Even, for example, fluctuations in the voltage will not affect the revolutions. Due to the constant revolutions, the pump system always gives the same performance.
We must differentiate between pump output and circulation performance. Unlike the constant pump output, the circulation performance of the filter declines, as it becomes more contaminated. The running noise can become louder with increased contamination of the filter.
The reduction in circulation performance is, from our experience, generally due to:
- dirty filter media
- incorrect filter layer set-up
- hose set-up or other accessories set-up
- contamination in the hose set-up and in the pump chamber
- incorrect filter start-up
We recommend that you take the following measures to guarantee optimum, trouble-free filter operation:
- Clean the filter media. Remove the filter media from the filter basket and rinse them through in lukewarm water. Depending on the model, fine filter pads and filter wool must be changed with each filter cleaning.
- Check that your filter layering set-up is done according to our recommendations, see
- Check the hose set-up for possible kinks or restrictions
- Clean the whole hose installation regularly. Clean the inside of the inlet, the outlet as well as the inlet tube, spray bar and the hose connectors on the filter (adapter, shut-off taps) several times in a push-pull motion using an EHEIM Universal Cleaning Brush No. 4005570. Another important task is the regular cleaning of the pump chamber, as well as the cooling and grease channel, with the EHEIM Brush Cleaning Set No. 4009560 (see instruction manual on maintenance and care).
- Start up the filter by priming, (see instruction manual). Please take care, that the water outlet (pressure side “OUT”) is situated above the water surface level during filing. This is the optimum way to avoid air entrapment in the filter.
How often should an external filter be cleaned?
There are no fast rules for this, because there are too many factors which influence the cleaning intervals, such as size of aquarium, fish stocking, type of plants as well as type and quantity of food. We therefore recommend that you only clean the filter when the pump output noticeably decreases.
A period of 8 weeks between cleaning should, however, be possible; with shorter cleaning intervals bacterial activity will suffer.