Biopower 160 internal filter by Eheim The external filter technology in the aquaball concept The water at the bottom is pumped to the top through the different filter layers using external filter technology and multi-layer filtration, and it is then redirected into the tank after filtration. EHEIM SUBSTRATpro is already in the closed filter baskets. It is also possible to use other filter media. A filter cartridge for the mechanical-biological prefiltration is located in the inlet basket. Additional filtration is provided by a filter pad in the pumphead holder. You can change the filter volume as needed by adding or removing filter modules, also known as filter baskets. Use ExtensionSET2 to extend the filter. The filter baskets have an Easy-Klick Locking System that makes it simple to clip them together and release them. Because of the modular design, the media or filter cartridges