Seachem Matrix Bio Media, 4 Litre

I use Matrix across all four of my aquariums, and it’s become my “buy once, trust always” biological media. It’s reliable, easy to use, and delivers the same steady performance no matter which filter I drop it into—canister, HOB, internal, or a sump basket. What I notice in day‑to‑day use The fish stay happy and the water stays stable. Matrix gives beneficial bacteria tons of room to colonise, which helps process waste efficiently and keeps parameters on an even keel. It’s properly “set and forget.” Once it’s in place, I don’t have to babysit it or swap it out every few months. A quick rinse in old tank water during maintenance is all it usually needs. It doesn’t crumble or compact like some ceramic rings. The pieces keep their shape, so flow through the media stays consistent. Ease of setup Rinse it once to remove any dust, pop it into a media bag, and place it after your mechanical stage (sponges/floss). That way, debris is caught before it reaches the Matrix, and the bacteria get clean, well‑oxygenated water. It works in small and large amounts—handy if you’re seeding a new tank or boosting capacity in an established one. Maintenance & longevity I only swish it in tank water when I’m doing a water change. No fancy routines or chemicals required. Because it lasts for years, it’s great value. You’re not constantly replacing media, so the cost evens out quickly—especially if you’re running multiple tanks like I am. Performance tips from my setups Don’t overpack the media bag; allow water to flow through freely. Keep a decent mechanical pre‑filter ahead of it. Less gunk on the Matrix means healthier bacterial colonies and less cleaning for you. It’s not a substitute for water changes, but it makes the system far more forgiving between services. Verdict Matrix is my go‑to for a reason: consistent results, low effort, and excellent durability. After trying plenty of alternatives, this is the one I trust across all four aquariums. For me, it’s the platinum standard of biological media—simple, effective, and worth every penny.

Just what I needed for my 105l tank setup,using this inside my Oase 350 thermo filter as ive got an over populated tank and wanted something that would thrive and keep the good bacteria going along with a good clean up crew this has made clean up less of a thing and only needing to do top ups. Would highly recommend and will be using in my next setups aswell.

Completely renewed my Fluval 407 filter with this, Fluval foam, extra ceramic rings and new carbon packs, the water quality is amazingly clear after only two days!

Very good stuff and easy to start and maintain cycle

Very good product, delivery took over a week so that why only 4 stars

This stuff has been a game changer in my setup. I was weekly having to do around a 50% water change to keep my nitrates in check as they were nudging up to 40ppm sometimes. My tank is a well stocked freshwater mostly American Cichlid tank. I have been running 1 litre of this stuff for the last 3 months and my weekly nitrate check is now more like 5ppm. My last weekly water change was more like 20% and still nitrates have stayed this low. I run it in a sump in the last section with the return pump and heaters, I was careful to make sure the flow is within the range this stuff is meant to be effective. I'm so impressed that I've put another litre in, it does take sometime to get to work but excited to see if it will go even lower.

I always recommend to swap the pre-installed foam filter media for Matrix, yes, it's expensive but totally worth it. I have put 2kg into my Oase Biomaster 250 and water is crystal clear.

Good!

De lo mejor en Material filtrante biológico. Bastante poroso y ayuda a albergar bastante bacteria benéfica para cumplir con la filtración de nuestros acuarios

Product arrived as described. Very little powder and very few garbage stones. My thermo 600 took all x4l. Will update x4 months from now on performance changes. Replaced ceramic rings and sintered glass bio balls from Ehiem. Make sure u wash thoroughly and soak for 24hrs to keep the floaters to a min. Update; working well in my 600, all my values are 0 and the water is crystal clear with just a little yellow due to wood in tank. All x4l went into my 600, flow is good with the 45ppi ring sponges on pre filter. Taken x7 weeks for these results. PH is stable at 7 to 7.1 Great stuff but still expensive!

Seachem Matrix is a great natural medium for colonizing both nitrifying and denitrifying bacteria so important for good water chemistry and the health of one's aquarium inhabitants. I noticed many users have complained about receiving an adulterated product, and frankly I thought I had received one as well. I called Seachem and got the scoop. Here's what I found out: Matrix is a natural, mined product. The mineral has natural variations in size and color. When mined, black Obsidian is sometimes included in the take. The Obsidian is removed by hand before packaging, but some slips into the container from time to time. The packaging does not have a tamper-proof seal beneath the lid. When you open the jar, you immediately see the product. Matrix is sold by volume and not by weight. A minimum weight is listed in the literature (e.g.: 1 liter of Matrix = 400 gram net weight) but this is required by law, and has nothing to do with the actual weight of the product, which can vary greatly due to Matrix absorbing moisture from the air, for example. The 1 liter of Matrix I received weighted 967 grams out of the jar. When you receive Matrix, expect it to vary in color, size, and that there may be a few dark or black rocks in the jar. Now for the actual use. Matrix provides a tremendous amount of surface area. The outer surfaces and crevices provide a very hospitable environment for the aerobic (oxygen consuming) nitrifying bacteria that make up the 'bio filter' so critical to breaking down Ammonia to Nitrite, and Nitrite to Nitrate. It's benefit doesn't stop there. At the end of the aerobic portion of the Nitrogen Cycle, nitrate is left to build up in the water column, and is one of the major pollutants that dictate the frequency and quantity of water changes. Nitrate can be reduced to Nitrogen gas - but this is an anaerobic (oxygen deprived) process requiring another type of bacteria. Nitrate laden water seeps into the core of Matrix after having been stripped of oxygen by the aerobic bacteria on the medium's surface. This oxygen-poor environment is perfect for colonizing anaerobic bacteria that consume Nitrate and release inert Nitrogen gas. This final step in the Nitrogen Cycle helps control the buildup of Nitrate in the aquarium, contributing markedly to the long term health of it's inhabitants.

Sembrano semplici pietre ma in realtà sono molto di più. Osservando al microscopio le insenature che presenta Seachem Matrix si capisce presto il perché siano i migliori materiali biologici per acquari. Offrono una grandissima superficie di insediamento dei batteri "buoni" indispensabili per un buon equilibrio dell'acquario. Il materiale è molto poroso e molto leggero. Nessun'altro materiale biologico per acquari da me testato ha le performance di Seachem Matrix. La porosità è elevatissima, ciò permette di massimizzare la superficie da colonizzare da parte dei batteri "buoni" presenti nel filtro. Più superficie=più batteri buoni. Più batteri buoni=meno alghe. Tali batteri legandosi al materiale biologico decompongono sostanza organica che inevitabilmente si forma in vasca. La materia organica è prodotta da pesci e piante e a livelli elevati, può diventare molto pericolosa per l'equilibrio chimico e biologico della vasca stessa provocando esplosioni indesiderate di alghe. Per il mio acquario da 100LT ho utilizzato 1LT di Matrix da inserire nel filtro esterno e ho avviato. Successivamente ho inserito nell'acqua della vasca circa 15ml di batteri liquidi che aiutano il processo di colonizzazione nel filtro. Possono essere inseriti anche in filtri interni. Dopo circa un mese di utilizzo alghe sparite! Provare per credere. E' un materiale eterno che può durare anni ed anni e non va mai sostituito; basta avere l'accortezza di sciacquare una volta ogni 40-60gg tale materiale nell'acqua di cambio della vasca (non in acqua di rubinetto pura in quanto contiene cloro che uccide i batteri presenti). Ogni filtro per acquari di acqua dolce deve essere equipaggiato con materiale biologico di ottima qualità come questo. Consiglio l'acquisto. P.S. Se ti sono stato utile fammelo sapere :)

I have used Seachem Matrix for well over a year now, and I can say for a fact that it is by far the best media out there, and the results I have had using it prove it. Every bio media will give your filter the surface area to grow aerobic beneficial bacteria that convert ammonia and nitrites into nitrates. What's so special about Matrix is that each piece of the bio media is so porous yet dense that there are nooks and crannies in each piece that a special type of beneficial bacteria is able to grow, specifically anaerobic bacteria. This anaerobic bacteria consumes nitrates. This type of beneficial bacteria is one that can only grow in environments that are not oxygenated (which is why the porosity and nooks and crannies Matrix bring to the table are important). I keep African Cichlids (Mbuna specifically), which have a reputation for being some of the most demanding fish when it comes to bio load. I keep the tank stocked moderately, overfiltered, and chalked full of as much Seachem matrix as I can fit. Before switching to Matrix I was using the typical ceramic rings and doing weekly water changes. My Nitrates would get up to 30-40 PPM after 1 week with no ammonia and no nitrites. After switching to Seachem Matrix and giving the anaerobic beneficial bacteria a couple months to establish itself, it is a night and day difference. I test my water weekly. I was shocked to begin seeing a decline in the numbers on my nitrate tests. Probably around the 6 month mark or so, there began to be such a little amount of nitrates that I could skip water changes. I keep everything recorded in a spreadsheet and there was one point that I went 2.5 weeks without a water change and my nitrates were only at 25 PPM, KEEP IN MIND THESE ARE FULL SIZE MBUNA WITH NO PLANTS IN THE TANK. I still do weekly water changes and test my water weekly, but typically there is so little nitrates that it wont even register on a dip test strip and API registers between 0 and 5 PPM. Truly amazing. The proof is in the pudding, Seachem Matrix makes big claims and much like every other Seachem product, it backs them up. 10/10 would recommend, I will never run another bio media in any tank.