Seachem Matrix Bio Media, 1 Litre

Good media works well in my canister filter, super clear water and water conditions/ tests are excellent

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.

Great product helped my tank with nitrates highly recommended Keeps water crystal clean

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

Used matrix on my discus tank years ago and ammonia and nitrates always 0 and 0 . nitrate we're 30 or 40 ppm by the end of week , but after 4 or 5 months nitrates hovered around 15 ppm with no other changes to set up . I did have double the amount recommended and it took 2 months to cycle a brand new tank. So 6months from adding to notice a lowering of the nitrates but that's still excellent . But I wouldn't use any other bio media and I've just bought more for a smaller 200ltr tank .

Does what it says

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.

Bon

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.

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!

Ya estaba harto de que el agua siempre estaba blanquecina y usando todo tipo de material filtrante. Al agregar Matrix a los filtros y al cabo de unos cinco días el agua se volvió cristalina. Lo recomiendo.

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.