Keep your aquarium clean and healthy by growing beneficial bacteria with Fluval Biomax Bio Rings Filter Media. One of the most important ways to maintain good water quality and keep your fish thriving is seeding your aquarium with good bacteria. This bacteria breaks down harmful ammonia from fish waste and other organic matter and starts the aquarium nitrogen cycle. Fluval Biomax Bio Rings Filter Media have a complex pore system creating an optimal environment where this beneficial bacteria can thrive. These small， cylindrical filter media have more capacity than most biological filter media， allowing aquarium water to have optimal contact time for efficient biological filtration that reduces and controls ammonia.