Seachem Matrix 20 Litre

Matrix is a high porosity bio media that provides efficient biofiltration for the removal of nitrogenous waste. Matrix is a porous inorganic solid about 10 mm in diameter. Each liter of Matrix provides as much surface (>~700 m²) as 170 liters of plastic balls! Plastic bio-materials provide only external surface area, whereas Matrix provides both external and internal macro-porous surface area. These macropores are ideally sized for the support of nitrifying and denitrifying bacteria. This allows Matrix, unlike other forms of bio media, to remove nitrate along with ammonia and nitrite, simultaneously and in the same filter. Matrix is completely inert and will not breakdown. It need not be replaced. Since the majority of the bacteria are internal, Matrix may be rinsed when needed without damaging the filter. Matrix is compatible with all types of wet or wet-dry filters.

Use 500 mL of Matrix for each 200 L (50 gallons*) of water. Matrix may be placed in any kind of filter, and is particularly effective in a canister filter. Matrix is sufficiently large that no filter bag should be required for most applications. Matrix works well in drip tray systems, but you may find that the larger Pond Matrix is better suited for such applications.

Setup & Use

What it is. A high-porosity biological filter media: porous inorganic stone, roughly 10 mm across, built to carry a bacterial colony rather than just move water through it. This 20 Litre pack is the same media sold in IndieFur’s 100 Litre size, dosed identically per litre of tank water.

Why the porosity matters. Seachem states Matrix carries over 700 m² of surface area per litre, most of it inside macropores rather than on the surface, unlike a plastic biomedia, which only offers external surface. Those macropores are sized specifically to support both nitrifying bacteria (on the surface, aerobic) and denitrifying bacteria (deeper in, anaerobic), so a single media handles ammonia, nitrite and nitrate together rather than needing a separate anaerobic stage.

How and where it goes in. 250 mL of Matrix per 200 L (50 US gallons). In the filter’s flow order it goes last: mechanical filtration first, chemical media second, Matrix (biological) last. Works in any wet or wet/dry filter; Seachem recommends a canister filter for best results.

Maintenance. Completely inert and doesn’t degrade or need replacing: rinse it in old tank water when it needs cleaning, without harming the bacterial colony living in it.

Freshness & Storage

Every batch we dispatch carries a minimum of 6 months’ remaining shelf life. Store this product in a cool, dry place away from direct sunlight, with the cap or inner foil closed tightly after each use.

Filter media and substrates carry no manufacturing or expiry date: their working life begins on first contact with water, not on the shelf.

Returns & Replacement

Returns are accepted within 7 days of delivery, provided the item is unused and in its original packaging. Manufacturer-sealed items cannot be returned once the seal is broken, and sale-priced items are not refundable.

If your item arrives defective or damaged, message us on WhatsApp with your order number, or email us if you would rather, and we will replace it. Approved replacements are delivered within 3 to 5 business days. Transit damage is covered by insurance on every shipment. If tracking shows delivered but nothing reached you, tell us within 48 hours, which is the reporting window Indian couriers allow. Damage caused during installation or use is not covered; replacement spares for such cases are chargeable.

Full terms are on our Cancellation & Returns page.