What is the Best Filter Media for Aquariums?

When it comes to keeping an aquarium’s water clean and clear, a filter provides only part of the solution. The media that is inserted into the filter can be more crucial to a healthy tank.

What follows is a discussion of the advantages and properties, as well as reviews, of the best filter media for your aquarium:

  • Fluval Biomax Filter Media
  • Marineland Canister Filter Bio-Balls
  • Marineland Black Diamond Media Premium Activated Carbon
  • Two Little Fishies ATLPB2 Phosban
  • Aquatic Experts Premium True Dual Density Aquarium Filter Media
  • Eheim AEH2507051 Mech Filter Media for Aquariums

The Types Of Filter Media

All of the different types of filter media out there fall into one of three different categories, all of which help to maintain a healthy living space for your fish.

Biological Media

With this type of media, colonies of “good” bacteria form on the surface of the various media used. These colonies help to break down dangerous ammonia into less harmful nutrients. This process is called the Nitrogen Cycle. While bacteria colonies can form in locations such as in the aquarium gravel, they can thrive in a filter’s media.

Chemical Media

Chemical media are used to remove undesirable chemicals from the water column as it passes through the tank’s filter. Over the years, this type of media has developed to the point that specific chemicals can be targeted by using certain products. A well-balanced tank that is easier to maintain can result from these materials.

Mechanical Media

A media designed for mechanical filtration pulls unwanted debris from the water as it passes through the material. The size of the holes that water passes through determines the size of waste it is able to trap. As with the other categories of media, mechanical media needs to be cleaned regularly in order to work efficiently.

A Quick Note About The Nitrogen Cycle

This process is critical for a healthy aquarium. Many beginners struggle with grasping the concept of how the cycle works. The expert staff and veterinarians at Petco’s website explain the Nitrogen Cycle in their article “Filter Functions and types: How to Choose the Right Kind of Aquarium Filtration.” (https://www.petcoach.co/article/filter-functions-and-types-how-to-choose-the-right-kind-of/)

How To Use Filter Media

The exact application for a media type will be determined by the type of filter used. Variations among brands and models will also factor into how a media is used. Even with these particular demands, there are some general ways that media is used within a filter.

Loaded Loosely Into The Filter

Most filters offer an area for media to sit in. Larger materials such as ceramic pieces, filter wool, peat, and sponges can be placed loosely into a filter. Some models provide trays to stack the media into.

Bagged Media And Cartidges

Some media are too small to place loosely into the filter. They can begin to move throughout the filter and into the tank itself. This requires them to be placed in a bag to keep them in place while the filter is running. Some media types are available in cartridges that can be inserted into a filter and replaced when they become clogged.

Using Multiple Media Types

A filter will most likely use a combination of biological, chemical, and mechanical filter types in its system. This is accomplished by layering the media in stacks or in multiple trays. As a former fish shop manager, the author of “Filter Media Types Guide” on Advanced Aquarium Concepts discusses the order each media should be placed in.

Water should begin filtration with coarse mechanical materials, followed by finer mechanical media to filter out chunks of debris and waste. General chemical filtration is next, followed by media that target specific chemicals. The final layer should house the filter’s biological media.

Cleaning And Maintaining Filter Media

The media in a filter must be cleaned regularly for it to work efficiently. Certain media, such as cartridges, must be replaced to keep water chemistry balanced. Cleaning is easily done using water from the aquarium, as this young hobbyist demonstrates in this video.

Materials Determine The Type Of Filtration

As Neale Monks from Wet Web Media discusses, the materials used will determine the type of filtration provided. Ceramics and filter wool make great biological filters, while gravel and sponges are good for mechanical filtration. Activated carbon provides a general chemical filter that leeches organic compounds.

Some materials provide multiple methods, like coral that provides biological filtration and raises the PH levels of the water at the same time.

Other Considerations

For many aquarium keepers, materials that are easier to maintain are preferred. Media that is contained in bags or cartridges are the best choice for convienece, they are quick to install and remove. The type and size of media used will often be determined by a filters design and manufacturer’s features. The fish themselves can determine the filter, especially if it affects the water’s chemistry.

Filter Media Reviews

Fluval Biomax Filter Media

A media that provides a large surface area for growth.

Fluval’s Biomax filter media comes in a 17.63-ounce quantity. The material is loose, which is an advantage for those who prefer to bag their own media.

Shout-Out!: It can function in either fresh or salt-water.

The material provides great biological filtration, thanks in part to the large surface area each piece provides for bacterial colonization. It has a porous surface that will provide even more room for bacteria to grow. The materials used in making Biomax will not alter the water column’s chemistry.

Call-Out!: This media can crumble in as little as six months.

A center hole in media piece promotes water flow within the filter. This media is easily cleaned by rinsing it off with water from the aquarium.


  • Quite affordable for the quantity offered by a big quality brand
  • This media will work in fresh or salt-water tanks
  • The media can be placed loosely or bagged


  • This media will require regular replacement
  • The pieces may be too large to use in a small hanging filter

Marineland Canister Filter Bio-Balls

An economical media that promotes simple biological filtration in aquariums.

Marineland’s Bio-Balls come in a pack of 90. The material is light and is packaged loosely. These design features are great for a tray in a canister filter. Its floating properties trap larger fish waste and debris as it passes.

Shout-Out!: The balls will not take up a lot of room in a tray.

Each ball is hollow, and the walls are constructed with even spaced slits. This not only promotes water flow in demanding conditions such as those found in canister filters, it provides a lot of surface area as well.

Call-Out!: Saltwater use should be limited to a fish-only aquarium.

The balls are highly durable and should not wear-out. Cleaning is done with a simple rinse in aquarium water.


  • The material is durable and will not need replacing
  • It comes at a low price point
  • The wide openings promote great water flow in canister filters


  • This media does not promote nitrate-removing bacteria
  • The design elements serve canister filters only
  • Saltwater use should be limited to fish-only aquariums

Marineland Black Diamond Media Premium Activated Carbon

An activated carbon that comes in a uniform grain size.

This 22-ounce offering from Marineland provides enough material to chemically filter most tanks. The granules are uniform in character and come loose, a feature that allows it to work with most filters.

Shout-Out!: The carbon is available in three different quantities.

The manufacturer is an established name in the hobby, and their premium quality product line is capable of providing double the carbon filtration power of other brands. The grains should offer greater longevity than cartridges filled with low-quality active carbon.

Call-Out!: The package may contain dust-sized particles.

Not only does the Marineland Premium act as a chemical filter for general water treatment, it does a good job of removing discolorization and odors as well.


  • The loose grains are more economical than pre-filled carbon cartridges
  • Proper water flow is achieved through a uniform grain size
  • This premium activated carbon should require fewer change-outs


  • It does not absorb any of toxins within the Nitrogen Cycle
  • The activated carbon may remove medications placed in the water column

Two Little Fishies ATLPB2 Phosban

A specialized chemical media that keeps phosphates at manageable levels.

Two Little Fishies Phosban is sold in a 150-grams volume per bottle. The material is loose and will require bagging before adding the media to a fish tank filter.

Shout-Out!: This material does not alter other water conditions.

While Phosban will not serve as a general chemical filter, its main benefit is using this media to reduce high levels of phosphate within the water column. It will also provide removal of silicas that can be found in water as well.

Call-Out!: This product is expensive for the quantity offered.

The product is safe to use in any fresh or salt-water environment, and should not change other chemical levels aquarium occupants may need.


  • It works great for removing phosphate and silica from the water
  • Is able to be used in both fresh and salt-water environments


  • This product does not provide a general chemical filtration for fish tanks
  • The material must be placed in a filter bag to avoid floating debris in the water column

Aquatic Experts Premium True Dual Density Aquarium Filter Media

A polyester fiber media that can be cut to fit.

This Dual Density filter media comes in a 1.0 x 6.0 roll that is easy to cut. The material is 100-percent polyester and provides a thickness ranging from three-quarters to one-inch in thickness. The manufacturer provides this material in other sizes as well.

Shout-Out!: The material safe to use in tanks with small fish.

This media provides removal of smaller debris and fish waste that a coarser mesh would allow through. It is durable, yet easy to cut with scissors.

Call-Out!: The fine woven mesh must be cleaned often to prevent water blockage.

This material works well with non-fish aquatic environments as well.


  • Its fine texture can trap smaller debris and fish waste particles
  • The material is dye-free to prevent discolorization of the tank’s water
  • This material can be cut to fit almost any sized aquarium


  • This finer material may inhibit water flow if not properly maintained
  • The trimmed edges of this material may snag on filter parts

Eheim AEH2507051 Mech Filter Media for Aquariums

A coarse media that works well on larger debris particles.

Eheim is an established name in the European aquarium market, and their Mech Filter Media comes in a one-liter bag. This material is also available in a larger five-liter container. Each ring is roughly a half-inch in size and would suit most fish keepers as a coarse pre-filter material to trap larger food and plant debris.

Shout-Out!: It can be used for a long time before it needs to be replaced.

The rings are macaroni shaped, and the center hole prevents this material from blocking water flow, even if cleaning and maintenance have been neglected a bit. The material is safe to use in fresh or salt-water.

Call-Out!: This media works best in canister filters.

A rinse before use will prevent dust from entering the water column, and these rings are chemically neutral.


  • The design will not inhibit water-flow
  • It will clog less often than sponge media does
  • This material is easy and quick to clean up


  • This media requires a good rinse before use
  • It will only trap larger debris and fish waste

The Winner

After reviewing the previous aquarium filter media, we feel that the Fluval Biomax Filter Media provides the best overall filtration. As a biological media, this material supports the growth of bacteria colonies that are crucial for the development of a healthy Nitrogen Cycle. The open center and porous surface provide ample room for colonies to establish themselves on each piece of Biomax.

The media is easy to maintain, and occasional gentle rinsing with aquarium water should provide a proper clean. This material can be used in a variety of filter systems. It is also safe to use in either fresh or salt-water aquariums.

The material used to make the media is chemically neutral, so it will not alter the water columns chemistry beyond the Nitrogen Cycle. While it will break down and require replacing, these features coupled with a low price point more than justifies that trade-off.

No matter which filters you decide to use in your aquarium, we hope that this article cleared up any questions regarding the use of filter media!

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