Seachem MatrixCarbon is a truly unique activated carbon. It is formed as a spherical bead for optimum hydrodynamics, and will not pack. Seachem MatrixCarbon permits maximum water flow and contact with its high density of macroporous binding sites. Seachem MatrixCarbon has a very low ash content as indicated by its minimal impact on pH. Even when added to distilled water, it does not raise pH above 7.0. While all carbons contain phosphate, regardless of false claims to the contrary, Seachem MatrixCarbon has the lowest detectable leachable phosphate content of all major carbon brands tested. Seachem MatrixCarbon outperforms other high grade carbons by at least two-fold when compared for total capacity to remove aquarium organic matter, rate of adsorption, and duration of use.While carbon is generally considered to be a chemical filter, that is not precisely true. It is in fact a mechanical filter as well, but it is only capable of mechanically filtering objects of molecular size. It func