Anyone who knows their way around fish tanks and fishes probably already know how important it is to keep the water clean and ammonia free. Smelly, murky water is the number one reason behind most setups failing. But keeping an aquarium clean with all the fishes and the wastes isn’t as easy either. It requires a few techniques, one of them being the very popular bio filtration system. In fact bio filtration is a must in every aquarium. There are heaps and heaps of bio filters (in fact filter media) in the market today, but today we have our eyes set on the very popular Seachem Matrix Bio Media.

The Seachem Matrix Bio Media has been the talk of the town for the longest time, and many aquarists swear by it. So what’s the deal? Is it just hype, or is there really some magic to it? Let’s find out!

Seachem Matrix Review: How Good Is This Bio Media

Seachem Matrix at a Glance

The Seachem Matrix Bio Media, at first look, looks pretty much like stones or pumice. These are some very high porosity ceramic-like stones which, at a closer look, offer larger pores than what we have previously seen. Alright then! So far so good, but what’s next?


The Seachem Matrix Bio Media feels and looks like small and lightweight stones. These are apparently made from naturally mined and chemically inert material. They sort of resemble, in both texture and hand feel, your aquarium pumice stones. They can be used as if or inside bags to suit any sort of aquarium filtration set up. Despite being so lightweight and porous, the Seachem Matrix Bio Media do not float away and stay pretty stationery where you want them to be.

Filtration and Bacteria Growth

Porosity and high surface area are hands down the 2 most important factors that goes into the making of a good bio filter media. The Seachem Matrix Bio Media, like we mentioned before are highly porous and interestingly offers pores that are a lager in size than regular. Apart from this, this bio filters has one of the highest surface areas among bio filters in its range. Every liter of the Seachem Matrix Bio Media provides over 160, 000 sq. cm, or 170 sq. ft, of surface which is equal to over 10 gallons, or 40 liters, of your typical plastic ball bio media!

What about the growth? Well, with the size and porosity and density of these things, the growth of good bacteria is inevitable! Thanks to the texture and the heavily porous interior of these beads, they are able to sustain large colony of bacteria and as a result support more bio-load in the aquarium compared to other bio filter media.

Water Compatibility

Not every bio filter media will work on all waters, and it is very important that you know what goes where if you don’t want to be disappointed. The Seachem Matrix Bio Media can be used with just about any setup. One of the best things about this particular bio filter media is that it is super low maintenance. Just rinse them with the tank water, and that’s’ it! But the best part about the Seachem Matrix Bio Media has to be that they never need to be replaced! Not does just save you the energy, but it also saves you dollars in the long run.


  • Lightweight
  • Does not float away
  • Highly porous
  • Immense surface area
  • Can accommodate both nirtifying & de-nitrifying bacteria
  • Never needs to be replaced


  • Sometimes packaged in lesser volume than stated

Seachem Matrix Vs Pumice


The confusions start with the similarity in appearance of Matrix and garden center pumice. The term pumice indicates many types of stone and they have different value for porosity or chemical property. With Matrix, you are assured to not leach anything in your tank water. Also it will never alter the pH of your aquarium.

There are certainly other bio-media available in the market. Beneficial bacteria don’t have any preference over brand! Rather they choose porosity and the oxygen condition of their surroundings. Bacteria will grow on almost any surface submerged in the water. So which media is the best to use in your filter depends on a few criteria.

The first criteria is surface area. The greater the surface area, the more bacteria can colonize. Providing surfaces to colonize is the main job of any bio-media.

Second criteria is the type of surface area the bio-media provides: internal or external? Some media like bio-balls increase surface area, while allowing water to flow freely through it, but all of the surfaces are external. Aerobic nitrifying bacteria can grow quite well on them, but can easily be washed away if rinsed or exposed to air for too long. Bio-media with high porosity like Matrix or Substrat Pro, Ceramic ring will also have some internal surface area. This will ensure available surface for bacteria colonies while also providing some protection to them against being washed away or dried out during filter maintenance.

Next criteria is the size of pores in the medium. The bigger the pores, the smaller the surface area. On the other hand, if the pores are very, very tiny, the surface area might be great but then won’t work well as a bio-media because of bacteria not being able to grow in the small volume inside the pores. Also efficiency of passing fluid will decrease.

All pumice is porous, but pore size and density varies greatly. And you have no guarantee of the size of those pores when you buy some intended for other uses.

Seachem Matrix Vs Eheim Substrat Pro & JBL MicroMec

Other than Seachem many well known brands are also selling biological filter media and among them Eheim & JBL are surely two big names. Both Eheim Substrat Pro & JBL MicroMec claims to have larger surface area than Seachem Matrix. But what scientific data tells us the truth? According to this study the BET-nitrogen specific surface area results are listed in the table below:

Seachem Matrix Vs Eheim Substrat Pro & JBL MicroMec

BET surface area measurements indicate that Matrix contains nearly 10 times the specificsurface area of Substrat Pro, and more than 20 times the specific surface area of MicroMec. Check out the study paper to know more about the experiment in details. So, it’s obvious that we got our winner in Matrix!

Frequently Asked Questions (FAQs):

Will this bio media filter manipulate the pH of my aquarium water?

That’s a great question! No, the Seachem Matrix Bio Media is specifically designed to make sure that it does not affect your water’s pH. The integrity of the water is only improved and never messed with.

I know that it never needs replacement, but is it reusable in another aquarium system?

Absolutely. The Seachem Matrix Bio Media does not need to be replaced like many bio filter media do. You can refresh these stones by simply running them under lukewarm or room temperature water. And they can be used in another aquarium setup with no problem at all!

How do you recommend we clean the Seachem Matrix Bio Media? And how often?

Knowing how to clean these media are extremely important if you want to maintain and sustain the good bacteria. Water too hot or too cold could kill them off. Water with a high pressure flow would wash them off. What you want to do is clean them under softly running water that’s around room temperature. Also make sure that the water does not contain chlorine or bleach in them. A cleanup every 2-3 month sounds okay, but you need frequent cleanups if your aquarium is loaded with fishes!

Would you recommend the Seachem Matrix Bio Media for use inside turtle tanks?

We don’t see we why you can’t. However, we also recommend that you use a larger tank and more of the Seachem Matrix Bio Media than just a liter. Turtles are awfully messy sometimes and you will need the extra filtration!

How many liters would you recommend for a 160 gallon aquarium?

1 liter of the Seachem Matrix Bio Media seems to do okay with 80 to 100 gallon setups, so 160 gallon should need at least 2 liters.

Final Words

There you go, guys! The Seachem Matrix Review! What do we think about it? Well, there’s definitely something to it. It is undeniably doing a good job. But it lacks is its consistency. It works for some, does not for other. There’s always less of the product packaged in the jar than stated on the pack, and much of the stones are said to be pretty much like gravels! This inconsistency and is a major headache for us so we think we’ll let this pass.

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