undergravel

Two different undergravel filters, which operate according to the flow-through principle or the suction principle.

undergravel filter flow-through principle by EHEIM:

The cleaned water is passed through the bottom of the soil, flooding the dirt particles and bringing them into the suction area of ​​the filter.

undergravel filter suction principle by EHEIM:

The suction principle operates in the opposite direction and acts as an additional surface filter. 

It is especially suitable for seawater aquariums and unplanted pools.