My external filter makes loud, gurgling noises.
This is most likely due to a small bubble appearing periodically in the pump head of the CristalProfi which is then transported out of the filter.
If air enters the filter system, this may be an indication that a seal is no longer tight or that connecting pieces don’t close tightly. As there is constant slight low pressure during operation, this is not necessarily noticeable. In the event that there is a leak of this kind, you can test by switching off the filter temporarily, in which case a small amount of water would escape where the leak is. Please note: This test should only be carried out with careful monitoring.
Be sure to check the hoses on the inlet side for air pockets or fine streams of bubbles. Often this is merely because the hose no longer fits securely into the JBL InSet.
Another possibility: The filter material may be very heavily soiled, which can result in the formation of fermentation gas which is periodically pressed out of the filter.
Please restart the filter as follows:
Remove the water from the body of the filter and the hoses. Make sure that the two small stopcock levers on the pump head are in the “OPEN” position. During the following start up procedure, the water outlet pipe with the spray bar, etc. must be positioned ABOVE the surface of the water for optimal ventilation of the appliance. Press the “START” button on the pump head repeatedly with the palm of your hand until water begins to flow into the suction hose (hose on “IN”). Wait until the filter has filled completely with water and the water in the hose leading to the water outlet pipe (hose on “OUT”) is at the same level as the surface of the water in the aquarium. Connect the filter to the mains power supply. The water will now flow out of the water outlet pipe and into the aquarium. At first, it may be mixed with air that is still trapped between the layers of the filter media. Gently shake the filter to dislodge the air which will escape with the stream of water.