Seachem Matrix is a high-porosity biomedia for aquarium filters that provides vastly more surface area for beneficial bacteria than standard filter media.

The porous stone-like media provides both external and internal surface area for bacterial colonisation. Supports aerobic bacteria (ammonia and nitrite removal) on external surfaces and anaerobic bacteria (nitrate reduction) within the internal pores. This dual action makes Matrix one of the few filter media that addresses all three nitrogen cycle stages. Suitable for freshwater and marine.

Matrix's ability to support anaerobic denitrification within its porous structure sets it apart from standard biomedia, providing nitrate reduction that most filter media cannot achieve.