Matrix™ is a high porosity biomedia that provides efficient biofiltration for the removal of nitrogenous waste. Matrix™ is a porous inorganic solid about 10 mm in diameter. Each litre of Matrix™ provides as much surface (>~700 m²) as 170 litres of plastic balls! Plastic bio-materials provide only external surface area, whereas 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™, unlike other forms of biomedia, 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. Matrix™ is compatible with all types of wet or wet-dry filters. Matrix™ may be placed in any kind of filter, and is particularly effective in a canister filter. Use with Stability to more rapidly establish the bio-filter.