Seachem matrix is a highly porous media designed to provide exceptionally efficient bio filtration for single site removal of ammonia nitrite and nitrate from freshwater marine and reef aquariar each litre of matrix provides over 160 000cm2 170 sq ft of surface equivalent to over 40 l 10 gallons of typical plastic ball mediar directionsr use 500ml of matrix for each 200 l 50 gallons of water matrix may be placed in any kind of filter and is particularly effective in a canister