Seachem Matrix Filter Media Aquarium Fish Tank Biological Bacteria Porus. Seachem Matrix is a high porosity biomedia that provides efficient biofiltration for the removal of nitrogenous waste. Matrix is a porous material that offers a high surface area for beneficial bacteria to colonize. It supports both aerobic and anaerobic bacteria species, helping to control ammonia, nitrite, and nitrate levels in your aquarium. This filter media is ideal for all types of aquarium filtration systems. It is a crucial component for maintaining a healthy and stable aquatic environment, supporting the biological filtration needs of your fish tank. The porous nature of Matrix provides an enormous surface area of over 700 m2/L, facilitating rapid colonization by nitrifying bacteria.