Premium Grade Liquid Filter Medium Helps biologically break down food residues, ammonia, and nitrite Provides a stable area for beneficial purification bacteria Creates a biologically active living environment Toxic substances such as ammonia and nitrite are continuously formed in aquarium water. Sera Bio Nitrivec, a product from Sera's biological technology, contains millions of purification bacteria that support the formation of a stable biological balance quickly and reliably, ensuring the continuous breakdown of formed toxic substances. The added volcanic mineral rock removes pollutants, effectively binds with turbidity, and provides a suitable stabilization area for purification bacteria. For healthy, clear, and biologically active water. Allows fish to be added after 24 hours when used with Sera Aquatan! Suitable for volume Suitable for 50 ml 125 liters / 33 US gallons 100 ml 250 liters / 66 US gallons 250 ml 625 liters / 165 US gallons 500 ml 1,250 liters / 330 US gallons 2,500 ml 6,250 liters / 1,650 US gallons 5,000 ml 12,500 liters / 3,300 US gallons