Seachem Matrix Carbon | Premium Activated Carbon for Freshwater & Saltwater

Seachem Matrix Carbon is a premium spherical-bead activated carbon engineered for both freshwater and saltwater aquariums. The bead form won't pack down in your filter, so flow stays high and every gram of carbon stays in active contact with the water. It pulls dissolved organics, tannins, odors, discoloration, and residual medications out fast — and it does it without spiking pH or leaching phosphate the way cheap carbons do.

Looking for more filtration media? Browse our Filter Media & Cartridges, or check the full Seachem collection.

• Spherical bead shape — won't pack, maximizes flow and water-to-carbon contact
• High macroporous binding-site density — adsorbs organics, tannins, odors, and dissolved meds
• Lowest detectable leachable phosphate of any major carbon brand tested — reef and planted-tank safe
• Very low ash — minimal pH impact (won't push pH above 7.0 even in distilled water)
• Outperforms other premium carbons by 2× or more on capacity, adsorption rate, and service life
• Suitable for freshwater and saltwater — reef, planted, FOWLR, community

Rinse Matrix Carbon under fresh tap or RO water before use to remove any fines. Place in a media bag and position it in your sump, canister, or HOB filter where flow passes through it. Use approximately 65 mL (about ¼ cup) per 20 gallons (75 L) of tank water for typical maintenance, or up to 250 mL per 20 gallons after dosing medications.

Replace every 4–6 weeks for routine polishing, or sooner after pulling out medications, large water changes, or unusually heavy bioloads. Carbon is not regenerable — once spent, swap it out.

Important: remove or skip carbon when actively dosing reef supplements, fish medications, or plant fertilizers — carbon will strip them out before they can do their job.

• Filter media bags — keep carbon contained and easy to swap
• Other filter media — pair with biological media (Matrix, Pond Matrix) and mechanical floss for a complete filter stack
• Seachem Prime, Stability & other water care — round out a maintenance kit

Is this safe for reef tanks and planted tanks?
Yes. Matrix Carbon has the lowest detectable leachable phosphate of any major carbon brand tested, so it won't fuel algae the way cheap carbons can. It's our default carbon recommendation for reef and high-tech planted setups.

Will it lower or raise my pH?
No meaningful shift. Even when soaked in distilled water it doesn't push pH above 7.0 — the ash content is far lower than typical bituminous carbons.

Do I need to rinse it before use?
Yes — a quick rinse under tap or RO water clears any fine carbon dust that built up in shipping. Pour through a media bag, drain, and you're ready.

How often do I replace it?
Every 4–6 weeks for routine polishing. After pulling out medications or after unusually heavy bioloads, swap sooner. Carbon isn't regenerable — once it's saturated, it's done.

Can I run carbon while dosing meds or reef supplements?
No. Carbon strips medications and many trace elements. Pull the carbon while dosing, then add fresh carbon afterward to remove residuals once treatment is complete.