The biOrb single service kit is suitable for one filter change and includes a replacement filter cartridge, algae cleaning cloth and sachet of water preparation chemicals. The algae cloth helps to remove green algae that may form inside the aquarium and the chemicals assist in keeping the water clear and clean to provide the best environment possible for your fish. The easy filtration change system in the biOrb is effective and simple to do, which is beneficial to the fish and the fish keeper. A filter change is recommended every 4-8 weeks. Use with the BiOrb 8 Gallon Aquarium (item #86387).