High performance filter medium especially for smaller aquariums. Spare filter media especially for sera fil 60 and 120. sera siporax min Professional allows maximum increase of the settling surface for purification bacteria but has a compact shape at the same time. This allows biological filtration even when using smaller filter units. The water parameters stabilize lastingly the maintenance effort is reduced.Filter and breakdown processes in the bottom ground of natural waters are very important. Organic waste are processed by micro-organisms and are thus available for the natural cycle as a nutrient for aquatic plants pollutants such as ammonium nitrite and nitrate are removed. Since little waste per water amount is formed in nature the present bottom surface is sufficient for housing a sufficient number of micro-organisms.However an aquarium accommodates a small biotope in little space. It is therefore necessary to maximally enlarge the settling area for ensuring complete and safe breakdown of organic remainders.sera perfectly put this into practice with the unique high performance filter medium sera siporax.Unlike other filter rings available on the market sera siporax consists of sintered glass. The unique material convinces due to a special three-dimensional pore structure. This allows maximum surface increase. At the same time the fine pores provide ideal settling conditions for bacteria that break down pollutants. Since it is an interconnected system the bacteria are permanently rinsed by water nd so can break down pollutants with best possible efficiency. Furthermore the unique pore array allows for self-purification of the substrate and thus very long filter holding times.In combination with specialized bacteria sera siporax even fulfills a variety of other special tasks such as algae prevention or directed water conditioning.