Seachem Matrix Biological Filter Media

Seachem Matrix is a biological filter media made of highly porous natural stones. This listing is the 4 L / 1 gallon tub. Its job is to house the bacteria that process ammonia and nitrite, and its deep pores can also support the slower bacteria linked to nitrate reduction.

Surface area

Seachem says each liter of Matrix provides over 170 square feet of surface, which it compares to over 10 gallons of typical plastic ball media. More surface means more room for bacteria in the same filter space.

Where it works best

Matrix can go in any kind of filter, but Seachem notes it is particularly effective in a canister. Canisters push water through the media steadily, and the closed space suits the deep pores. It also works in sumps and in a mesh bag inside a hang-on filter.

Setting it up

• Rinse it in dechlorinated water to clear dust.
• Place it after mechanical sponge or floss so the pores stay clear.
• Give it time. Bacteria need weeks to colonize new media.

Care

Don’t replace Matrix on a schedule. When you service the filter, swish it in old tank water to remove trapped debris. Tap water can harm the bacteria you’ve built up.

Freshwater and marine

Matrix is made for both freshwater and marine tanks. It doesn’t leach anything into the water, so you can use it in reef systems.

How much to use

A 1 gallon tub fills the bio trays of a mid-size canister with some left over. If you run several tanks, it can be split between filters.

When moving Matrix from an old filter to a new one, keep it wet in tank water the whole time. That carries the established bacteria across and avoids an ammonia spike in the new setup.

Alternatives

For ring-shaped ceramic media, look at Fluval BioMax or Sukh ceramic rings.