Seachem Matrix is a highly porous biomedia that provides efficient filtration for the removal of nitrogenous waste and is 10 mm in diameter. Each liter of Matrix provides as much surface (>~700 m2) as 170 liters of plastic balls. Matrix provides both external and internal macroporous surface area. These macropores are ideally sized for the support of nitrifying and denitrifying bacteria. This allows Matrix to remove nitrate along with ammonia and nitrite, simultaneously and in the same filter. Matrix is completely inert and will not breakdown. It need not be replaced. Since the majority of the bacteria are internal, Matrix may be rinsed when needed without damaging the filter and is compatible with all types of wet or wet-dry filters.