Keeps the filter biologically active and reduces sludge. Contains live starter bacteria and sludge-decomposing cleaning bacteria. Breaks down ammonia, nitrite, organic pollutants such as fish waste, sludge accumulations, food, and plant residues. Reduces filter sludge, extends cleaning intervals, and increases filter performance. Promotes the bioactivity of the substrate, prevents decay, and reduces maintenance effort. Wide spectrum of bacteria to maintain biological activity after water changes and filter cleaning. Tetra FilterActive 250 ml starter bacteria ensure clean water and healthy fish. The unique formula of live starter bacteria and sludge-decomposing cleaning bacteria accelerates the biological breakdown of pollutants such as ammonia, nitrite, fish waste, sludge, and food residues. This not only keeps the filter clean for longer but also extends the cleaning interval and increases filter performance. With Tetra FilterActive, the bioactivity of the substrate is promoted, decay is avoided, and maintenance effort is reduced. Ensure optimal filter performance and a healthy aquarium life with Tetra FilterActive. Dosage: Shake well before use. After filter change or cleaning, add 5 ml per 20 liters of aquarium water. 1 mark on the measuring scale corresponds to 10 ml. Half dosage after water changes.