MatrixCarbon — Macroporous Spherical Activated Carbon 250 ml, 500 ml and 4 L - Seachem

Seachem MatrixCarbon is an activated carbon formed into spherical beads from macroporous bituminous coal. The only spherical carbon on the market, it will not pack, permitting maximum water flow and contact with its high density of macroporous binding sites. It outperforms other high-grade carbons by at least two-fold in total capacity to remove aquarium organic matter, rate of adsorption, and duration of use.

Main advantages

• The only spherical activated carbon on the market — will not pack, maximum water flow
• Macroporous bituminous coal — targets large organic molecules (nitrogenous waste, yellowing compounds)
• Outperforms competing carbons by at least 2× in capacity, adsorption rate and service life
• Lowest detectable leachable phosphate content of all major carbon brands tested
• Very low ash content — does not raise pH above 7.0 even in distilled water
• Three sizes offered: 250 ml, 500 ml and 4 L

Directions (Seachem)

250 mL will easily treat 400 L (100 US gallons) for several months. Rinse before use and place in a filter bag. For best results, position MatrixCarbon so as to maximize the flow of water through it: a canister filter, chemical filtration module, box filter, or any high-flow area of a trickle filter.

Official dosing table

Macroporous or microporous: why it matters

The ingredients a carbon is manufactured from determine whether it will be macro- or microporous. Carbons made from coconut shell and other organic products form microporous carbons, which mainly remove metals and trace elements — better suited to air filtration. Carbons made from bituminous coal, like MatrixCarbon, form macroporous carbons, which target large organic molecules — better suited to aquarium water filtration.

Carbon is generally considered a chemical filter, but it is in fact a mechanical filter as well — capable of mechanically filtering objects of molecular size.

Phosphate and activated carbon

All carbons contain phosphate. That phosphate comes from the ash of the carbon source, not from washing the carbon with phosphoric acid, contrary to what is sometimes claimed: most carbons are washed with sulfuric acid. The main purpose of acid-washing is to remove ash. Because of MatrixCarbon's spherical hydrodynamic properties, more ash is washed from it than from any other carbon — giving it the lowest detectable leachable phosphate content of all major brands tested.

Available sizes

• 250 ml (net weight 100 g)
• 500 ml
• 4 L

Rounding out your filtration

• Seachem The Bag — the fine-mesh filter bag to hold the media, as recommended by the manufacturer
• Seachem Purigen — selective, regenerable organic resin; using it with carbon extends its useful service life
• Seachem PhosGuard — the phosphate and silicate stage of the same chemical filtration chain
• Seachem Matrix — the biomedia that comes next: Seachem recommends the order mechanical → chemical → biological

Frequently Asked Questions

Why does MatrixCarbon's spherical shape matter?

A spherical pellet has ideal hydrodynamic properties: it allows maximum water flow and contact, without the compacting and channeling typical of granular activated carbon. Granular carbons create dead zones where water no longer circulates; MatrixCarbon uses up all available adsorptive sites before exhaustion.

How long does MatrixCarbon last?

Actual time depends on initial water conditions. In very dirty water, it may last as little as a few hours; in very clean water, several months. In general, 3 to 6 months is typical.

Is MatrixCarbon compatible with Purigen?

Yes, the two are complementary. MatrixCarbon removes a broad range of organic compounds and dyes, while Purigen selectively targets nitrogenous organics. Using carbon alongside Purigen extends Purigen's useful service life.