Filter Technic Undergravel Filters

EHEIM undergravel filters use the aquarium substrate as a large filtration area. The current range includes systems based on the throughflow principle or the suction principle, as well as an extension set. The correct version depends on the aquarium layout, planting and intended direction of water flow.

With the throughflow principle, filtered water is directed through the substrate, while the suction principle draws aquarium water through it. These operating modes have different requirements and should not be selected solely by aquarium dimensions. Follow the stated suitability for planted or unplanted aquariums and choose a substrate that permits reliable water movement.

Plan the plate area, uplift or connections and any extension modules before adding the substrate. Once the aquarium is established, changes are difficult. Prevent zones with blocked flow and maintain the system according to the manufacturer's instructions.