What Is Aquarium Filter Media?

Date Posted:23 April 2022 


Whether you own an aquarium or are thinking about getting one, it’s important you understand how to keep the water in your tank clean and clear. This is where filter media comes in.


Understanding Filter Media Basics


Filter media is essentially anything placed in an aquarium filter to ensure the basic requirement of clean water is met in your aquarium. Aquarium filter media allows the good nitrifying bacteria to trap and break down fish waste, thus providing safe environmental conditions for your fish.


How Does Filter Media Work?


There are three overarching types of filter media you’ll find in aquariums: mechanical, biological and chemical. Different filter media play different roles in the various stages of the filtration process in your aquarium.


1. Mechanical Filter Media


Mechanical filter media is used in the first stage of filtration and helps in getting rid of any physical debris that may be found in your aquarium’s water. Physical debris mainly includes visible solid particles such as faecal waste, decaying plants, uneaten food and sludge, and also smaller particles such as dust.


Filter pads and foam sponges are generally used as mechanical filter media. They usually come in three grades based on the thickness of their pores: coarse, medium and fine. When water goes inside the aquarium filter, it passes through the mechanical medium, which will capture all the solid waste. The water can then be filtered through to the next filter media.


2. Biological Filter Media


The second stage of filtration in any modern aquarium involves the use of biological filter media. What this does is clean the water of any nitrification residue, like ammonia and nitrites, that fish leave behind. By fostering the growth of nitrifying bacteria that thrive on ammonia and nitrites as a food source, the water can be cleaned of those pollutants. This is where biological media comes in, as it provides housing for these beneficial bacteria.


Biological filter media has a large surface area and is usually very porous, hence allowing the good bacteria to colonise within it. In some water filters, biological media comes pre-installed, but, if not, it is quite easy to jump online and buy the medium of your preference, and install it in your filter.


Seachem Matrix is regarded as one of the best biological filter media available. But there are lots of other biological filter options, including ceramic noodles, ceramic substrates, and some are even made of sintered glass like the Aqua One PremiumNood, Aqua One Premium Sub or Ehiem SubstratePro.


3. Chemical Filter Media


While the first two stages of filtration are absolutely necessary, chemical filtration can be an extra step to get the best filtering system for your aquarium. What this does is absorb and remove any dissolved organic substances and impurities from the water, making it cleaner.


Popular types of chemical filter media include activated carbon, carbon cartridges, resins, ammonia removers, phosphate removers and other absorbent chemical media.


Activated carbon or resin media, like Seachem Purigen or API Bio Chem Zorb, are extremely powerful at clearing cloudy aquarium water. They effectively remove organic compounds dissolved in the water and tannins from driftwood which discolour the water.


In terms of installation, activated carbon can either be placed in a power filter where the water is pumped forcefully through it, or inside a filter bag that lets water flow through it.


But Do You Need Filter Media?


There’s no ifs or buts when it comes to filter media in your aquarium; it’s an essential for ensuring a clean and safe environment for your fish. Without filter media, the fish in your aquarium can be exposed to ammonia, nitrates and nitrites, and other pollutants, like dust and metallic residue. As a result, your fish may experience a loss of appetite, discolouration, lack of energy, diseases and, in some cases, even death.


Should You Clean or Replace Filter Media?


The answer to this question depends on the filter media in question. Mechanical media should be cleaned periodically, and be replaced once it looks dirty and loses its sponginess. Foam sponges can easily last up to a year, while filter pads should be replaced every couple of months. Biological media should ideally be replaced every 1–2 years, while chemical media, like carbon and carbon cartridges, should be replaced every couple of months.


These time frames are indicative and can vary on a case-to-case basis, so it’s good practice to follow what is mentioned on the product packaging or in the user manual.


When cleaning your filter media use water from the aquarium rather than tap water to rinse out the filter media. Tap water contains chlorine which will kill the good bacteria living in the filter media that break down the fish waste. This is generally the most common cause of cloudy water in an aquarium and it will take time for the good bacteria to build back up again before the water clears up.


Buy Your Filter Media Today


At Aquarium Kingdom, we pride ourselves on having a massive collection of all the filter media that you could ever need, and all at reasonable prices. We also have other great aquarium supplies and offer superb customer service, making us your one-stop aquarium shop. If you have any questions about filter media and your aquarium, don’t hesitate to get in touch with us today!