Seachem Matrix™

Matrix is a porous inert biological medium, which is to say it is the surface your filter's nitrifying bacteria live on.

Key features

• Highly porous stone offering far more bacterial surface than smooth plastic bio-balls of the same volume
• Pores run right through the material, so colonies establish inside the medium as well as on it
• Inert and does not break down, so it is not a consumable on a replacement schedule
• Can be rinsed in old tank water when it clogs, without wiping out the bacteria living deeper inside
• Works in canisters, sumps, drip trays and hang-on filters

Biological media is what carries a tank through the nitrogen cycle, converting ammonia to nitrite and nitrite to nitrate. Those colonies take weeks to populate, which is why you never rinse the media under the tap or swap all of it at once.

The pieces are large enough to sit loose in most filter baskets, though a media bag keeps them tidy in an open chamber. For biological media in other brands, see external filter media. Local pickup at our Lethbridge store.