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The 11 Best Bio Filter Medias For Reef Tank Setups

As such, aquariums rely heavily on biological filtration systems.

Fish waste contains ammonia and nitrates, which are released into the water along with the waste of other organisms and decaying matter.

Ammonia and nitrate are extremely harmful to fish and must be removed from the water and decomposed.

Biological filtration is used for this purpose, but it requires certain media to work properly.

Despite the ubiquity of biological media, not all of these formats are created equal.

Some biological media are better suited for saltwater aquariums, while others work better in freshwater systems.

Keep in mind that saltwater tanks have slightly different biological filtration needs than freshwater tanks.

Anyway, today BestForPets (bestforpets.org) will assist you in determining the best bio filter medias for reef tank setups for saltwater (our recommendation), so let's get started!

Guide to Choosing the Best Biological Filter Media

Before you rush out and buy the first “best biological filter media” that you come across, there are a few factors to keep in mind. Let’s talk about the most important things to remember right now.

Using Bio-Media Balls: The Pros and Cons

There is more than one form and shape of bio media available, but one popular option is bio media balls. It’s up there with the most common kinds out there.

Let’s quickly examine the benefits and drawbacks of utilizing bio media balls before you make a final buying decision.


  • Possibility of bacterial colonization over a large surface area.
  • Usually have high rates of water flow
  • Most frequently promote extensive water-to-media interaction
  • Cost less than normal
  • Are exceptionally sturdy and long-lasting
  • Are typically non-reactive and harmless to the chemistry of water


  • When compared to the forms of other media, they tend to take up a lot of room.
  • Because of how often they become blocked and unclean, they are not ideal.
  • When comparing the wet and dry portions of a filter, the dry portion is where bio balls excel.


First, you must evaluate the permeability of the medium in issue. There is a general correlation between the amount of surface area available for bacterial growth and the porousness of a substance.

The greater the bacterial growth on the medium, the higher the quality of the filtration. And the media’s impact on water flow decreases as porosity increases. This also aids filtration by increasing media-to-water contact.

Size and Form

Additionally, you should think about the dimensions and shape of the medium in question. This is especially important to remember if your aquarium, filter, and available media area are all on the tiny side.

If you’re looking for a new piece of media, it should have a form factor that harmonizes with the rest of the collection.

Filtration efficiency is enhanced when the media bits can be packed in as tightly as possible. However, remember that material that is excessively dense may likely slow down the water flow rate somewhat.

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Biological filtration may be accomplished with a wide variety of various media. Ceramic, plastic, glass, and natural pebbles are all good options for media. Now, obviously, some of these are superior to others, but they all share a fundamental trait.

Since they are all inert, they won’t alter the pH or anything else about the water’s chemistry and won’t cause any problems.

Classification Filter

We won’t go over every kind of filter there is right now, but remember that not every kind of material works well in every kind of filter. To determine the best filter media for the one you have, you should first learn about the filter itself.

Also, check to be sure that the filter material you are purchasing is suitable for the filter you now have. It’s crucial that you do some digging into this. Some bio media are more expensive than others, therefore it’s important to consider your budget.


In summary, BestForPets (bestforpets.org) thinks the above are some of the best biological means for saltwater filtration.

It is your responsibility to understand the level of biological filtration required and what type of media is the best bio filter medias for reef tank setups for your aquarium.

Once you have that information in hand, making a purchase should be easy. One of the most popular products is Fluval Media for Fluval Biomax Filters.


Media for Fluval Biomax Filters

These little bio ceramic rings are perfect for either saltwater or freshwater fish tanks (you can buy them here). There isn’t much to say about them, but you can be sure that they’re effective.

They are constructed of inert ceramic, which means they have no effect on the water’s quality, which is a major plus. Also, there are big canals there with plenty of small tunnels and porous places. Two primary advantages result from this.

Water may make extensive contact with and flow through Fluval Biomax Filter Media. For this reason, the filter’s flow rate will not be hindered, and the water will be thoroughly filtered as a result of the high bacteria to water contact ratio.

In addition, this Media’s porous regions encourage the growth of several beneficial bacteria that consume excess ammonia and nitrate.


  • Don’t take up a lot of room
  • No changes to water quality
  • Inundate the media with water.
  • Doesn’t change how quickly water moves through filters
  • Plenty of places for germs to hide and multiply


  • Extremely rapid deterioration and perhaps mold growth in the rings is to be expected.


The CerMedia MarinePure Bio-Filter Media

This filter media, unlike the ring-shaped variant, is constructed of simple balls. Of course, in comparison to the rings we discussed before, they do not have quite as much exposed area for the water to contact and move through, but they still function enough.

The inert ceramic construction of these balls means they won’t alter the pH level or cause any other problems. These may be used as bio media filters for bigger tanks, and they also perform well in such tanks.

This CerMedia MarinePure Media has been designed to be extremely permeable, allowing for the growth of an abundance of microorganisms.

This is wonderful news since it indicates that the ammonia and nitrates in your saltwater aquarium will be significantly reduced by using this material.

While it may seem like a lot, these items are designed to be so permeable that water can basically flow right through them. This not only keeps the filter flow rate high, but also increases the rate at which biological filtration is taking place.


  • Lots of places for germs to grow and spread.
  • Highly permeable, allowing for efficient water transport
  • Many forms of media interact with water.
  • The Larger the Filter or Aquarium, the Better!
  • The pH of a ceramic medium is unaffected.


  • It occasionally becomes plugged and is known for this


Bio-Media Filtering Technology by Aquatic Arts FilterPlus

When looking for bio medium for saltwater tanks, there is another choice that is both novel and somewhat cool.

It’s important to note that, unlike many other mediums, this is not ceramic. These particular media are constructed with raw materials extracted from American mines.

The bio-media used in Aquatic Arts filters is completely organic and has been mined from the soil. There are no chemicals involved, and this material never wears out or needs to be replaced.

For lack of a better description, these pebbles are quite porous and offer plenty of room for cultivating helpful bacteria. This area’s great for removing ammonia and nitrates since it has a lot of flat surfaces for bacteria to colonize.

However, it is important to note that they are not as permeable as other solutions. What we intend to convey is that water’s ability to interact with and flow through material is somewhat restricted.


  • Only uses organic ingredients
  • Avoiding the use of chemical solvents
  • Not requiring ever-renewing supplies
  • Does not affect the chemistry of water
  • An excellent media-to-water interface
  • Plenty of room for germs to spread.


  • Somewhat reduces flow rate
  • Wetness is reduced compared to rings and balls when dealing with media.


Prototype EHEIM Substrate

Among the several saltwater bio media options available, EHEIM Substrat Pro appears to be the favorite for a number of reasons. In the first place, this substance is constructed from a unique variety of glass that has been processed for this specific use.

Glass is extremely durable; it will not break down and will not support the growth of mold. Rather than throwing it out, you may just rinse it under the sink and put it to use again.

To put it mildly, the amazing lifespan of 6 months for EHEIM Substrat Pro is a major selling point.

The porous surface area and tiny tubes in EHEIM Substrat Pro provide efficient water drainage. These tiny glass pebbles are ideal for removing harmful ammonia and nitrates from water because of their porous surfaces.

This results in a high degree of water-to-media interaction while having no discernible impact on water flow. This material appears to be well-liked because it does not need a lot of storage space.

As an added plus, this substance won’t change the chemical or physical composition of water.


  • Simple cleaning and upkeep thanks to washability.
  • Does not require frequent replacement
  • Will not develop mold
  • Saves a lot of room
  • Many forms of media interact with water.
  • Extremely Permeable to the Growth of Bacteria
  • Does not affect the chemistry of water


  • Likely to shatter and crack easily
  • Susceptibility to wear and tear increases with increased water velocity


Bio-Balls from the Goats

This filter medium is suitable for both saltwater and freshwater aquariums, as well as ponds. The fact that bio balls and ceramic rings are included in the same package is quite neat.

You get the best of both worlds with this set, since both the balls and the rings are favorites of ours. The rings and balls are both constructed from ceramics and other materials that won’t affect the water’s chemistry, which is a big plus.

The bio balls are constructed with a high surface area for optimal bacterial growth, and they perform respectably in terms of water flow rates and water to media contact.

The rings are also designed to be highly permeable, which is beneficial for bacterial growth, water circulation, and media interaction with the liquid environment.

What makes Govine Bio Balls and rings so successful is that they can be made in a wide variety of sizes and forms to suit a variety of needs.


  • Leave the chemistry of water alone.
  • Balls and rings are included.
  • Has no effect on fluid dynamics
  • Many forms of media interact with water.
  • Extremely receptive to microbial colonization


  • It comes in quite small quantities.
  • Rings and balls tend to shatter quickly, and there are many of them.


Biological Filtration Media, Fluval G-Nodes

This bio media is awesome since it can be used in both saltwater and freshwater aquariums, making it a flexible and useful choice. The star-shaped design of the Fluval G-Nodes Biological Filtration Media is another bonus.

As a result, you can fit a greater quantity of them inside a bio media filtering chamber than you could with, say, a media that has a different form, like balls or rings.

Ceramic construction means Fluval G-Nodes Media has no impact on water chemistry. What’s more, it’s designed to be incredibly porous, which is great since it provides a lot of room for good bacteria to colonize.

These items are made with water flow in mind, maintaining steady water flow rates and exposing the water to a lot of different media.


  • Many forms of media interact with water.
  • Helpful for fluid dynamics
  • Does not affect the chemistry of water
  • Excellent bacterial colonization potential.
  • Shape-definition compactness


  • Have a tendency to deteriorate rapidly
  • It’s possible that it might get plugged up sometimes.


Seachemical Bio-Media Matrix

To further assure that Seachem Matrix Bio Media has no effect on the chemistry of the water, it is constructed from inert components. In addition, the neat thing about this is that it never truly has to be replaced, ever.

All you have to do is rinse it out when it becomes filthy.

Seachem Matrix Media has an exceptionally large surface area in relation to its size and weight. This implies that there is a lot of space for bacteria to thrive, and that a filter chamber may hold a lot of debris.

This allows for a high ratio of media to water for optimal filtration without significantly slowing water flow rates.


  • Has no effect on the chemistry of water
  • Never requires re-ordering
  • Possibility of bacterial colonization over a large surface area.
  • Doesn’t have a major impact on river flows
  • Inundate the media with water.


  • The porosity of rocks varies greatly.
  • A little increase in water hardness is a result of their presence.

Author Image

Dr. Barry Buttler

Dr. Barry Buttler, DVM, MS, DACVIM, is an experienced veterinarian who specializes in the care of small animals, specifically dogs. Dr. Barry K. Buttler is a member of the American Veterinary Medical Association and holds multiple certifications in small animal emergency medicine and geriatric pet health.

Veterinarian (DVM) Dr. Barry Buttler


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