The original sera siporax Professional is suitable for use in both freshwater and marine aquariums as well as in ponds. Maximizes the surface required for biological purification and provides the optimal substrate for the settling of necessary filter bacteria. Pollutants such as ammonium, nitrite and nitrate are removed. 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 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.