The Seachem Media Matrix Aquarium Filter is a high porosity biomedia that provides efficient nitrogenous waste removal via biofiltration. Matrix is a porous inorganic solid with a diameter of about 10 mm. Each liter of Matrix has the same surface area (>700 m2) as 170 liters of plastic balls! Plastic bio-materials only have an external surface area, whereas Matrix has both an external and an internal macroporous surface area. These macropores are perfectly sized for nitrifying and denitrifying bacteria. This enables Matrix, unlike other types of biomedia, to remove nitrate alongside ammonia and nitrite in the same filter. The Matrix is completely inert and will never degrade. It does not need to be replaced. The matrix can be rinsed without damaging the filter because the majority of the bacteria are internal. Matrix can be used with any type of wet or wet-dry filter.