Seachem Matrix Carbon is a truly unique activated carbon. It is formed as a spherical bead for optimum hydrodynamics, and will not pack. It permits maximum water flow and contact with its high density of macroporous binding sites. Seachem Matrix Carbon 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 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 functions through extremely small cracks and crevices, called macropores and micropores. Microporous carbons remove primarily metals and smaller ions (like trace minerals) and are best suited to air filtration, while macroporous carbons remove primarily larger organic molecules (like nitrogenous waste) and are best suited to water filtration.

Seachem Matrix Carbon is a bituminous coal-based, macroporous carbon. It is the only spherical carbon on the market, allowing for maximum water flow. It is sized to allow full penetration by water, but not small enough to escape filter bags.