Filter Media

What does Filter Media mean? (Easy Guide)

Choosing the right Filter Media is important in the aquarium hobby, but what does filter media mean? Understanding why and how it works should be the main focus. This very easy to follow guide will help in choosing the right media that fits your set up best.

Why do we need media in our filters?

The media in our filters is what actually cleans the water by removing waste products and toxic elements before returning it to your tank. Media also adds surface area for beneficial bacteria to grow on which is needed to complete the nitrogen cycle.

The nitrogen cycle in an aquarium is very important for the livelihood of everything in your tank, including fish, plants, and coral. Understanding this cycle will put you far ahead of the learning curve in your fish keeping journey. Watch this video for an informative, but simple explanation on the Nitrogen Cycle.

Order of Media

There are 3 primary stages of filtration that happen in your canister filter. They are Mechanical, Biological, and finally Chemical, in that order. No matter what type of filtration you use, be it a canister, hang-on back (HOB), Sump pump…etc. The order of filtration never changes.

Mechanical Filtration

When water enters your filter it must be mechanically filtered first. Mechanical Media consists of sponges and pads ranging from very coarse to very fine and everything in between. Water should hit the most coarse sponge first and work its way to the finest sponge before entering the next phase of filtration.

What this accomplishes is grabbing and trapping all the particles in your water. These particles consist of fish waste, excess uneaten food, decomposing matter, and basically anything floating around your tank that shouldn’t be there.

This stage of filtration is what produces that crystal clear water look we all want in our fish tank. If you’re having problems achieving this check this article out on Crystal Clear Aquarium Water.

Biological Filtration

Once your water has been cleaned and filtered of any detritus it enters the next stage of filtration, biological. Biological filtration is where your beneficial bacteria will grow and multiply. This is accomplished by adding surface area to your filter. There are many products that do a great job at providing this biological filtration.

Types of Biological Media

There are many products available that claim to be the best bio-media around. Listed are a few of the top brands (In no particular order) with their descriptions directly from the manufacturer. Keep in mind that all of these work extremely well.

Seachem Matrix

Seachem Matrix

Matrix is a highly porous media designed to provide exceptionally efficient biofiltration for single-site removal of ammonia, nitrite, and nitrate from freshwater, marine, and reef aquaria.

Each liter of Matrix provides over 160,000 cm2 (170 sq. Ft.) of surface, equivalent to over 40 L (10 gallons) of typical plastic ball media.

Fluval BioMax

Fluval Biomax

Fluval BIOMAX bio rings have a complex pore system creating an optimal environment where beneficial bacteria can thrive.

BIOMAX bio rings have more capacity than most biological filter media and allow ideal water movement throughout the media to ensure optimal contact time for efficient biological filtration for freshwater and marine environments.

Bio-Home Ultimate

bio-home ulitmateBio-home Aquarium filter media offers the best possible environment for bacterial colonization and is capable of supporting aerobic and anaerobic bacteria in a wide variety of filters and varied flow rates.

Being capable of supporting aerobic and anaerobic bacteria, ensures that natural processing of ammonia, nitrite, and nitrate can be achieved.


Chemical Filtration

What does filter media mean

The final stage of filtration is intended to reduce organic compounds, odors, toxins, medications, and dissolved metals in your water. Chemical filtration is not a necessary component and is usually added based on preference.

It can also help to amplify the clarity of your water but keep in mind that chemical filtration gets “used up” and must be replaced once consumed or it it can release all the additives right back into your water.

Types of Chemical Media

There are many products available that claim to be the best chemical media around. Listed are a few of the top brands (In no particular order) with their descriptions directly from the manufacturer. Keep in mind that chemical filtration is not necessary or required in your aquarium but can be used for specific applications. All of these listed work as advertised.

Marineland Activated Carbon

activated carbon

Marineland Black Diamond Media Premium Activated Carbon removes more discoloration, odors and impurities compared to our next leading competitor according to a 2015 University study.

Use this premium activated carbon for sparkling clean water that helps create the aquarium of your dreams. Marineland Black Diamond Media Premium Activated Carbon is ideal for all aquarium filters and is specifically sized to be more efficient.

Seachem Purigen

Seachem Purigen

Purigen is a premium synthetic adsorbent that is unlike any other filtration product. It is not a mixture of ion exchangers or adsorbents, but a unique macro-porous synthetic polymer that removes soluble and insoluble impurities from water at a rate and capacity that exceeds all others by over 500%.

Purigen controls ammonia, nitrites and nitrates by removing nitrogenous organic waste that would otherwise release these harmful compounds. Purigen’s impact on trace elements is minimal. It significantly raises redox. It polishes water to unparalleled clarity.

Chemi-pure blue

Chemi-Pure Blue

Chemi-pure blue is specially created for fantastic results in reef and marine aquariums. Our NEW proprietary blend of premium, low-dust pelleted carbon and high-capacity ion-exchange resins are skillfully combined to create a superior all-in-one filter media in a nylon bag.

Chemi-pure blue significantly reduces organic compounds and phosphates while raising redox and helping stabilize pH for a healthy, crystal-clear aquarium.


So what does filter media mean? It means the choice you make in filter media will affect the quality and cleanliness of your tank water as well as the overall health of your tank mates. Understanding how all this media works together will help you make a much more informed decision.

So keep your sponges clean, make sure you have enough bio-media for bacteria growth and the choice is yours if you’d like an extra boost by choosing a chemical media. Don’t forget to enjoy the journey!

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