sera siporax Nitrat-minus Professional is a high performance filter medium for biological nitrate breakdown with parallel breakdown of nitrite and ammonium. Denitrification is optimally enhanced and maximized by the bio polymer sphere matching the siporax ring. The degradable bio polymer serves as a carbon source for the bacteria that break down nitrate.The bio polymer sphere not only maximizes the biological filter performance of the unique sintered glass tube but at the same time also increases the holding time of the filter in two ways. Besides pollutant breakdown, the special construction of the sphere optimizes the water flow and thus improves substance transport into the inner siporax ring. sera siporax Nitrat-minus Professional therefore is an almost maintenance free and, above all, long lived filter medium. The number of water changes can also be reduced. Water parameters can be improved by siporax Nitrat-minus Professional especially in bigger and/or densely stocked community