Matrix 2 L — Biomedia 700 m²/L Nitrification and Denitrification | Seachem

Seachem Matrix 2 L is a high-porosity biomedia designed for efficient biofiltration and nitrogen removal in marine and freshwater aquariums. This 10 mm diameter porous inorganic solid provides a surface area of ​​over 700 m² per liter—the equivalent of 170 liters of plastic balls. Its ideally sized macropores simultaneously support nitrifying and denitrifying bacteria, allowing for the removal of ammonia, nitrites, and nitrates in the same filter. The 2 L format treats up to 1600 L (400 US gallons), making it ideal for large reef aquariums or sump systems.

Main advantages

• Surface area of ​​over 700 m² per liter — equivalent to 170 liters of plastic pellets
• Internal and external macroporous surface — supports nitrifying AND denitrifying bacteria
• Simultaneously removes ammonia, nitrites AND nitrates in the same filter
• Completely inert — does not degrade, never needs to be replaced
• Rinseable without damaging bacteria — the majority are lodged inside the pores
• 2 L size — treats up to 1600 L (400 US gallons), economical for large systems

Use in reef and marine aquariums

Matrix is ​​unique among biomedia because its macropores support both aerobic bacteria (which remove ammonia and nitrites) and anaerobic bacteria (which reduce nitrates). This dual action allows for complete biofiltration in a single filter. Seachem recommends placing the biological media last in the filtration order: first mechanical filtration (foams, filter floss), then chemical filtration (MatrixCarbon, Purigen, PhosGuard), and finally biological filtration (Matrix). Matrix does not affect the aquarium's pH.

Instructions for use

• 250 ml of Matrix per 200 L (50 US gallons) of water — the 2 L format treats up to 1600 L
• Rinse before use
• Place in a cartridge filter, media reactor, box filter, or any high-flow area of ​​the sump
• Large enough that a filter bag is not required in most applications
• Particularly effective in a canister filter or in a dedicated sump compartment
• Use with Seachem Stability to establish the biofilter more quickly

Interview

The Matrix filter does not wear out and never needs replacing. However, it can become clogged with debris and biofilm. Seachem recommends regular filter maintenance—about once a month as a starting point. Since the majority of bacteria are inside the pores, the Matrix can be rinsed with aquarium water to remove debris without damaging the biofilter.

Matrix vs de*nitrate

If Matrix keeps your nitrate levels stable but doesn't lower them, increase the amount of Matrix or add Seachem de*nitrate, which removes nitrates more effectively per unit volume at a flow rate not exceeding 200 L/h. For higher flow rates, Matrix supports anaerobic denitrification more effectively. The necessary anaerobic bacteria typically take a few weeks to colonize the internal pores.

Manufacturer's precautions

• Does not affect pH
• Completely inert — does not degrade
• Compatible with all types of wet or wet-dry filters

Available formats

• 250 ml
• 500 ml
• 1 L
• 2 L
• 4 L

Why choose the Matrix at ReefSolution?

The 2L size is the economical choice for large reef aquariums with sumps or systems over 100 gallons. To quickly establish your biofilter, combine Matrix with Seachem Stability. Complete your chemical filtration with Seachem Purigen for nitrogenous organics and Seachem MatrixCarbon for organic compounds and colorants.

Frequently Asked Questions

Is the 2L size sufficient for a large reef aquarium with a sump?

The 2L size treats up to 1600L (400 US gallons). For a typical 120-200 gallon reef system with a sump, the 2L size provides ample biological capacity. For larger systems, the 4L size is available.

Should The Matrix be replaced?

No. Matrix is ​​completely inert and permanent. A monthly rinse with aquarium water is sufficient to remove debris without affecting the internal bacteria housed in the macropores.

Does Matrix really eliminate nitrates?

Yes. Its macropores create internal anaerobic zones that support denitrifying bacteria, in addition to external aerobic zones for nitrification. It is the only biomedia that addresses ammonia, nitrites, and nitrates simultaneously. Results on nitrates appear after a few weeks of bacterial colonization.