Best Aquarium Filter Media: Guide to Bio Filter Media & More

You have your aquarium and you have your plan for what you are going to put into the fish tank.  You got your rocks and plants, you also have your fish and what kind of food to give them.  You have your canister filter for the water, but now you have to choose what kind of filter media you will put inside. Choosing the right filtration media is not a difficult task, but it is important to have an understanding of the types of filtration and its role. 

aquarium filter media

Different Types of Filter Media

There are three major kinds of aquarium filter media which are biological, mechanical, and chemical filtration media. Each of these types of filtration media plays a different role within the filtration system.

Biological Filter Media

Not all bacteria are bad.  Some of these bacteria break down dissolved solids into a less toxic form.  Biological filter media is anything inert that provides a space for this beneficial bacteria that allows for them to colonize.  This is an extremely important process that brings nutrients and oxygen to the nitrogen cycle.  These patches of biological filter media filter the water from ammonia and nitrates which the fish leave behind.  Biological filter media will be put inside the tank and keep the water free of these nasty particles. 

Mechanical Filter Media

Mechanical filter media is the first line of defense when it comes to filtration.  This is the type of aquarium filter media that captures the solid particles that float in the water.  These solids can come from decaying plants, uneaten fish food, or fecal matter.  Mechanical filter media brings water inside the filter, keep the solid waste, and pushes the clean water back into the aquarium.  However, mechanical filter media will need cleaning fairly regularly. 

Chemical Filter Media

Chemical media filter is sort of a last resort when it comes to cleaning your aquarium water.  Chemical media filters are used when you want to dissolve any organic substances that remain in the tank after the biological and mechanical filtration process is complete.  It is not used as often as the other two.  This can be in the form of activated carbons, resins, and other absorbents, which help maintain the water quality as the unwanted dissolved matter attaches to it.  However, chemical filter media needs to be replaced more often than biological media, so keep an eye on it. 

With these three types of filter media, it is important to plan ahead for which type works best with your tank to keep your water quality at its highest level.

filter media in canister filter
filter media in canister filter

Best Aquarium Filter Media

There are a lot of varieties within the three major types and it may be difficult to find the best fish tank filter media.  For that reason, here are some of the best quality choices from each filter media form.  Remember that proper fish tank media will be based on what is needed for your tank and the creatures and plants living inside it.  Choosing the best filter media will ensure that those things have a long and healthy life, so make sure to do good research before making any final purchases. 

Best Biological Filter Media

Fluval Biological Filter Media (Bio Rings)

Fluval is a very popular brand with aquarists and they have a wide selection of biological media.  One of their top products is the Fluval Biological Filter Media.  The pore system design allows for more capacity of bacteria than most other biological filter media.  This comes in a large pellet form and its target species is to help fish.  This filter media is amazing at supporting bacterial growth, maintains a very healthy nitrogen cycle in your tank, and is compatible with most canister filters. 


  • Great value for money
  • Popular biological filter media
  • Helps with nitrogen cycle


  • A bit on the larger side

EHEIM Substrat Pro Biological Filter Media

Another fantastic type of filter is the EHEIM Substrat Pro Biological Filter Media.  This is made of a highly porous artificial sintered glass material that is easily reusable.  All this filter media needs are some rinsing with aquarium water every one to three months, therefore only needs to be replaced every three to six months.  The shape gives a better through flow as it is more open than other filter media, which provides better colonization for beneficial bacteria. 


  • Reusable
  • Works with all EHEIM filters


  • A bit more expensive

Seachem Matrix

Seachem Matrix is a highly porous and inorganic solid biological filter media that catches any nitrogenous waste in your freshwater or saltwater aquarium water.  It works with any type of filter, but works especially will in canister filters.  Matrix is completely inert and does not breakdown at all, which means it does not need to be replaces.  This is one of the best biological filter media because it provides over 170 square feet of surface and does not affect the pH level of the tank water.  While the Seachem Matrix is a bit more expensive than other filter media, it is certainly worth it since you will never have to replace it. 


  • Does not need to be replaced
  • Easy to clean


  • A bit expensive

AQUANEAT Aquarium 1″ Bio Ball

The Aquaneat Aquarium 1″ Bio Ball is a sophisticated fish tank sump filter media that has a brand new design for maximum biological filtration.  It comes in a bag of 500 pieces and works with both freshwater aquariums, saltwater aquariums, sump, koi, and water garden ponds.  Inside the bio balls, the new design involves a bio-sponge which gives maximum filtration capacity.  They are made of polypropylene material, which make them a safe and reliable bio media.  It also comes with a free reusable bag for easy handling.  The Aquaneat Aquarium 1″ Bio Balls are easy to maintain and can be rinsed off very easily to ensure a quality amount of biological filtration.


  • New, unique design
  • Comes with free reusable bag
  • Great for many different types of water


  • More expensive

Biohome Ultimate Filter Media

Biohome has created the Biohome Ultimate Filter Media which is a very popular choice for biological filter media.  It is made from premium quality sintered glass and is extremely porous with its unique design and excellent for water absorption.  Biohome Ultimate Filter Media comes in packs of one pound, two pounds, or five pounds for whatever your tank needs.  This is a great fish tank filter media for canister filters, HOBs, and sump filters.  However, this aquarium filter media is a bit more expensive than most other brands because of its fast control of ammonia, nitrate, and nitrite levels.  It supports both aerobic and anaerobic bacteria through its unique structure.


  • Comes in variety amounts
  • Less water changes
  • Works with many different filters


  • Does not come with starter bacteria

Best Mechanical Filter Media

Aquapapa Bio Sponge Filter

The Aquapapa Bio Sponge Filter offers both mechanical and biochemical filtration and can last a very long time because it can be cleaned repeatedly.  This filter is a mechanical media that is cut-to-fit for any aquarium, koi pond, sump, or reef.  The sponge filter can be cut into many shapes for filtration in multiple types of situations.  Aquapapa made a sponge filter that is easy to cut and affordable.  It is perfect for catching all sorts of particles in any freshwater and saltwater tanks.  This is a great value for your money when considering mechanical filtration system.


  • Great value for money
  • Mechanical and bio chemical filtration
  • Can be used up to 16 times after cleanings


  • No instructions on package
  • May not be as dense as some need

Encompass All Premium 50 Micron Polishing Filter Pad

Another quality product for mechanical filtration is the Encompass All Premium 50 Micron Polishing Filter Pad.  This filtration system consists of fifty microns and has a dense fiber network that traps and contains any large particles and debris floating around in the tank.  The filter pad can be used in a wide variety of situations and can easily be combined with other carbon, nitrate reducer, and ammonia reducing pads to ensure clean water in your tank.  While it does require a little cleaning, the filter pads do a great job of filtering your aquarium water.  At an incredibly reasonable price, the Encompass Filter Pad is a fantastic value to add to your mechanical filtration system. 


  • Great value for money
  • Industry-leading
  • Works well with other filter media


  • Slight difficulty working with some tanks

FilterFirst Aquarium Filter Media

One of the most popular filter pads on the market, the FilterFirst Aquarium Filter Media comes in a wide variety of bundle sizes for whatever your aquatic situation requires.  These filter pads have 100-micron dense fiber network that catches whatever debris comes into the aquarium water.  They are environmentally friendly and can be reused many times before disposal.  This is the third generation of the FilterFirst Aquarium Filter Media which traps all kinds of particles with its two-layer density that combines the aquarium filter pad with a water polishing pad.  It is easy to use and is a good choice for a mechanical filter system. 


  • Two layered filtration
  • Good value for money
  • Comes in variety of bundle sizes


  • Use in a wet/dry filter might lead to clogging

Best Chemical Filter Media

Seachem Purigen

Another very popular choice for mechanical media is the Seachem “The Bag” Filter Media.  This is a filter bag that is welded instead of stitched and has a reseal able locking closure.  This mesh bag is resistant to bleach, caustics, and acids and is very reasonably priced.  The Seachem Purigen filter bag is one of the most advanced filtration media on the market today, as it is very well made for all types of aquariums, ponds, and other aquatic environments.  While they can be a little too big for some filters, they can also easily be adjusted to any custom size mesh bag to give your tank the filtration you need.  Check out the Seachem Purigen for a great chemical filter media.


  • Easily customized
  • Provides excellent filtration
  • High micron count


  • Seams are known to split

POLYBIO Poly Filter

The Polybio Poly Filter Pad is a chemical filter media that comes in pad form.  It removes any harmful organics, heavy metals, and toxic ammonia from the aquarium water and keeps the tank looking clear and clean.  It can work in power filters, under gravel filters, canister filters, and wet/dry sumps.  The Polybio Poly Filter is a quality chemical filter to consider for your tank.


  • Great at removing harmful particles
  • Reasonably priced


  • Small sized

Fluval Carbon Filter Media

Fluval also makes a brand of chemical filter media in the Fluval Carbon Filter Media.  This is one of the best and most efficient chemical filter media to use in your aquarium.  It can be used with most kinds of filters and provides a large surface area for absorption.  The Fluval Carbon Filter Media removes any harmful toxins from the water and comes with three 100-gram nylon bags to keep the media together.  For the best use, be sure to replace it every four weeks or so.  It is great for permanently traps organic waste and removes heavy metals, odors, any deals with any discoloration.  This is very flexible and useful chemical filter media to consider. 


  • Very popular brand
  • Comes with three 100-gram nylon bags
  • Works with many different filters


  • Not very long lasting

What order should you place aquarium filter media inside the filter?

When placing your filter media into your filter, it is important to remember the correct order in which to place them.  In most filters, the mechanical media is the first kind to go inside because it receives the raw flow of the water.  Since the mechanical media is responsible for removing the larger particles, it becomes the first line of defense in the filtration process. 

After the mechanical media is in place, you can then put in the biological media.  This media cannot get clogged.  The biological filter media is arguably the most important of the three as it would not be possible to maintain the tank water without it.  There is a lot of waster that fish create and all of that will sink into the substrate if it is not properly filtered out. 

Once the biological media is placed, the final portion will be the chemical filtration.  The chemical filter media cannot go first as it will clog and need to be replaced quite quickly.  If it is placed in front of the biological media, then the beneficial bacteria will not grow as well.  By placing the chemical filter media last, you are ensuring that the bacterial colonies will not be affected. 

How often should you clean filter media?

When handling aquarium filter media, you must keep an eye on how much gunk is starting to form on the filter itself.  Filter media needs to be cleaned off on a regular basis so it can work at peak efficiency.  With most filter setups, it is recommended that you have a cleaning session every four weeks or so.  However, if you are using a single sponge as your filter, then you may want to clean it once a week.  Generally speaking, mechanical filters need to be cleaned a bit more often than the others because it traps and holds most of the solid debris from the tank, so it can clog more easily if not cleared out.  Therefore, clean your mechanical filter media about once every month, but the chemical and biological filters can last a while longer before they need cleaning.

How often should filter media be changed?

Any kind of filter foam, sponge, or pads should not need cleaning sessions so often as long as you clean them carefully and make sure not to break them.  The filter media may be housing bacteria that you do not want to kill so rinse it carefully in the tank.  Mechanical media is involved with every kind of filter and should be cleaned and replaced at least once every month.  Something like filter floss can clear your tank very quickly but needs to be changed regularly. 

Carbon is one of the most common of chemical media types, which are great at battling cloudiness and removing odors from the tank.  It is recommended to change the filter cartridges once a month, which coincides with the amount of time it takes to fill up. 

Biological filter media can happen all over your tank in the form of bacteria.  Since these bacteria are so good for the tank, you must try to leave as much beneficial bacteria in your tank as possible when cleaning your filters or changing filter media. 

How do I clean an aquarium filter without killing bacteria?

The beneficial bacteria are paramount for the nitrogen cycle in the water and is vital for the health of your aquatic creatures.  Cleaning the aquarium filters without killing bacteria is pretty easy.  Here’s some tips on cleaning your aquarium filter.

  • Be sure to unplug to turn off the filter system
  • When siphoning tank water, make sure to use a clean bucket
  • Gently rinse any solid debris off filter pads, sponges, or bio-media
  • Only replace 25% of the water to keep the chemistry stable
  • Use old media to colonize new filters
  • Don’t replace water, clean filters, and clean decorations at the same time
  • Test the water several days after cleaning
  • Only clean filter media when necessary

By using the warm, de-chlorinated aquarium water to clean your filters, it is less likely that you will end up killing any good bacteria. 

How do I make a DIY filter media for my aquarium?

Not that filter media is particularly expensive or inefficient, but there are many safe household items that you can use to create your own filter media if you would like to save some money.  A pair of nylon pantyhose or cheesecloths can create a very useful media bag.  You can also use quilt cotton batting in place of sponges, which is sold at most fabric stores.  Just be careful to replace it often as it degrades in the water.  Instead of ceramic rings for your canister filter, you can exchange them for lava rocks, which give a huge rough surface area for bacterial colonization and are inexpensive compared to many products.

What filter media removed algae?

If you are having an issue with algae no matter how many water changes you go through, you will need to take a look at what kind of biological filter media you are using.  This filter media improves the nitrification process within the water and is imperative to maintain if you are keeping anything living inside the tank.  If you are working with a saltwater aquarium, you might want to look into ceramic media, which provides extra surface area for bacterial colonization.  This gives the beneficial bacteria more space for a foundation and can be extremely advantageous to cycling a new aquarium.  It never hurts to have additional surface area for your bacteria. 

If you are still getting algae inside your tank, then there is some nutrient that is making its way into the water which the algae really enjoy.  Using phosphate controlling media along with any kind of biological boosters for your filtration system will hopefully be able to pick up any slack.  All of the different kinds of filter media pick up their own set of issues within the tank’s water, therefore, filter media must be cleaned and maintained in order to keep any problems from occurring in the aquarium.

A more natural form of filter media would be adding more plants to your aquarium.  The more plants you have, the less chance algae have to take over.  This is because plants and algae fight each other for light and nutrients.  Plants are more likely to win this battle if given the proper conditions.  There are also several kinds of catfish that are easy to add to your tank that can help control the algae.

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