MatrixCarbon 4 L — Macroporous Spherical Activated Carbon | Seachem

Seachem MatrixCarbon 4L is the largest size in the MatrixCarbon range, a unique activated carbon formed into spherical beads made from macroporous bituminous carbon. The only spherical carbon on the market, it does not compact and allows for maximum water flow with optimal contact across its high density of macroporous bonding sites. MatrixCarbon outperforms competing premium carbons by at least two times in total organic matter removal capacity, adsorption rate, and service life. The 4L size is the most economical choice, ideal for large reef systems or aquarists who regularly replace their carbon.

Main advantages

• The only spherical activated carbon on the market — does not compact, maximum water flow
• Macroporous bituminous carbon — targets large organic molecules, ideal for aquatic filtration
• Surpasses competing carbons by at least 2x in capacity, adsorption rate and duration
• Lowest leachable phosphate content of all major brands tested
• Very low ash content — does not raise the pH above 7.0 even in distilled water
• 4L format — the most economical in the range, divisible into multiple treatment portions

Use in reef and marine aquariums

Activated carbon acts as both a chemical and mechanical filter at the molecular level. Macroporous carbons like MatrixCarbon primarily remove large organic molecules (nitrogenous waste, yellowing compounds), while microporous carbons (coconut) target metals and small ions. The spherical shape of MatrixCarbon solves the compaction and channeling problems of granular carbons—water flows uniformly through all the beads, utilizing all adsorption sites before exhaustion. Typical lifespan is 3 to 6 months, depending on the initial water conditions.

Instructions for use

• 250 ml treats 400 L (100 US gallons) for several months — the 4 L size treats up to 6400 L
• Rinse before use. Place in a filter bag.
• Position to maximize water flow — cartridge filter, chemical filtration module, box filter, or high-flow zone of a filter
• Typical duration: 3 to 6 months per portion depending on the organic load

Macroporous vs. microporous

Carbons made from coconut shells form microporous carbons that primarily remove metals and trace elements—better suited for air filtration. Carbons made from bituminous coal, such as MatrixCarbon, form macroporous carbons that target large organic molecules—better suited for aquarium water filtration.

Phosphate and activated charcoal

All activated carbons contain phosphate from the ash of the source material. MatrixCarbon has the lowest detectable leachable phosphate content of all major brands tested. Its spherical hydrodynamic properties allow for more efficient acid washing, removing more ash than any other activated carbon.

Manufacturer's precautions

• MatrixCarbon will have a minimal impact on trace elements but remains an aggressive medium — for more targeted selectivity, consider Seachem Purigen
• Can be used to remove Seachem Cupramine after treatment

Available formats

• 100 ml
• 250 ml
• 500 ml
• 1 L
• 4 L

Why choose MatrixCarbon at ReefSolution?

The 4L format offers the best cost per liter in the MatrixCarbon range for aquarists who regularly replace their carbon or maintain multiple aquariums. For even more selective and regenerable organic filtration, combine it with Seachem Purigen—using it together extends the life of Purigen. Place the MatrixCarbon in the Seachem The Bag for optimal use.

Frequently Asked Questions

Is the 4L format the most economical for large systems?

Yes. The 4L size is the largest in the range and offers the best cost per liter. It can be divided into multiple portions: each 250ml treats 400L of aquarium water for 3 to 6 months, so the 4L size provides 16 treatment portions.

Does MatrixCarbon add phosphate to the aquarium?

All charcoal contains phosphate from the ash. MatrixCarbon has the lowest leachable phosphate content of all the major brands tested, thanks to its more efficient acid washing made possible by its spherical shape.

Can MatrixCarbon replace Purigen?

The two products are complementary, not interchangeable. MatrixCarbon removes a wide range of organic compounds and colorants. Purigen selectively targets nitrogenous organics with minimal impact on trace elements and is regenerable. Use both together for optimal chemical filtration.