Biological filtering material for all types of pond filters, diameter 25mm. One liter provides a bacterial colonization surface equivalent to approximately 34 liters of ceramic filtering material. Prefiltration using fish food prevents large particles from entering the biofilter.

The material features many channels for anaerobic bacteria, while inside the channels there is a small amount of oxygen, which pushes the bacteria to break down nitrates to secure oxygen.

One liter is sufficient to clean 1000 liters of pond water with 20 fish each 10 cm long or corresponding inhabitants, with a total weight of about 1.5 kg when fed with high-quality food, 40 g daily.