Best Aquarium Filter Media Guide: Setup, Maintenance & Uses


Today’s world needs the best of everything – the best car, the best house, and the best of whatever exists. And this greed keeps expanding on and on and here we are, discussing the best filter. To achieve the most exceptional performance possible, almost all the aquarium filters use mechanical, chemical and even biological aquarium filter media.


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These kinds of mechanical, chemical and biological induced filtering mechanisms are very much crucial to maintain the ambiance of the aquarium. The aquatic organisms would have to be provided with clean and clear toxic-free water so that they are in the best of their health. ‘Best’ again.

So, in this blog, we will be providing all kinds of information necessary to choose the appropriate filter media for your fish tanks as well as their set-up and maintenance guides.

Mechanical Filtration and Its Respective Aquarium Filter Media

About Mechanical Filtration: How does it Work?

As the name states, this particular method of filtration uses a mechanical filter to capture particulate matter from the water in the aquarium.

These mechanical filters are said to be experts in filtering out solid wastes. Uneaten fish food, decaying plants or animals, fecal waste or whatever be it – nothing escapes the scope of the mechanical filters.

In another aspect, mechanical filters are very important with a filtration system because once this is employed, there might be lesser necessities for the use of chemical or biological filters, both of which end up being a strenuous process and have striking consequences.

In any aquarium you see, these mechanical filters are the basic filtering mechanisms and probably the best and less problem causing filter. They work to their fullest potential so that not even a hint of contamination is found in the aquarium.

Best Mechanical Aquarium Filter Media

Mechanical filter media are always in demand as they never fail to offer anything less than what is expected of them. The most popular kinds of mechanical filter media include foam, floss, and pre-filter media.

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These media are very easily available at any pet store and even online as decent prices without any compromise in its quality. But, these mechanical filter mediums are the DYI-type of things, so gather some stuff, put your hands to work and make yourself your very own media!

Mechanical Aquarium Filter Media Set-up

The mechanical filter media as mentioned above like foam and floss can be used in a packed form. For instance, the canister filter, power filter and other types of filters are mechanical filters in a packed version.

Let’s say your aquarium has a wet or dry sump filter system. In such scenarios, the water that drains into the sump can be run through a chamber of filter floss or other similar mechanical filter media.

A specially designed filter sock would be an excellent choice for this purpose. However, some people – Hobbyists especially prefer using aquarium skimmers instead of using mechanical filters. That is indeed a very clever choice as skimmers in many ways are better than traditional mechanical filters. Their efficiency in removing particulate matter is par excellence.

Mechanical Aquarium Filter Media Maintenance

Despite all of its mind-blowing qualities, mechanical filters have a slight let down. It might feel like a letdown for those users who are absolute couch potatoes.

So the fact is that these mechanical filters demand frequent cleaning. If you leave the filter unattended for a longer period of time, then with all the material it collects like decayed plant and animal wastes along with leftover food and feces, the rate of decomposition in the filters go up exponentially.

This situation would then demand the use of biological filters which totally denies the prime objective for the use of mechanical filtering media.


From a scientific point of view, if detritus is trapped on a particular media and it is forced to be under the effect of constant oxygenated water, then it breaks down at a faster rate and releases its nutrients which is essential for the flora and fauna of the mini aquatic ecosystem.

This can happen if and only if the filter media is kept under constant check and is cleaned from time to time. Else, the detritus would be left to decay at a random corner in the tank and the rate at which it breaks down and releases nutrients would be very slow as compared to the previous case.

The use of foam or floss media also has its own disadvantages. Once they become old and lose their ability to filter out the particulates, it is essential to get them replaced.

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However, the use of pre-filtration media would not need any replacement as they are durable and longer-lasting than the latter two. They definitely need cleaning, but replacements are out of the talk with pre-filtration media.

Biological Filtration and Aquarium Filter Media

Biological Filtration and It’s Working

All those living creatures that make up the mini aquatic ecosystem inside your house or office in the form of an aquarium excrete nitrogenous wastes. This applies to both vertebrates and invertebrates without any bias.

These nitrogenous wastes which have a very toxic nature would be totally detrimental to the ambiance of the aquarium and to the living entities it hosts. Biological filtration is a clever method of filtration that acts as an eye for an eye, except that there is no vendetta involved.

The fishes and the plants present in the tank are indebted to the bacterial microbes and algal growths that convert ammonia which is the prime toxic waste into nitrites and then nitrates.

This entire process of conversion happens is a part of a biological cycle called the nitrogen cycle. However, this conversion of ammonia into nitrate is called nitrification.

So, what is the meaning of the eye for an eye reference made earlier? The answer lies in the fact that biological filtration uses living organisms such as algae and bacteria to detoxify those wastes generated by the other creatures in the tank.

So one’s excreta turns out to be the business of another one in an aquarium that employs biological filtration. So this is what biological filters are designed to do – nitrification.

To promote the growth of nitrifying bacteria which demands to be in the presence of an oxygenated environment, fresh oxygen-rich water is allowed to run over the substrates that serve as the colony for the bacteria to grow.

To enhance your outputs, even more, the use of a mechanical filter would multiply the results to a great extent.

As the water is already filtered through the mechanical filter media, the water that passes over the bacterial substrate would be entitled to a contamination-free highly oxygenated supply of water which is exactly what is required for faster multiplication of the colony of bacteria.

Which is the Best Biological Aquarium Filter Media

The biological filter media are probably on the ‘most favorite’ lists of the nitrifying bacteria especially (if in case they ever have one). They turn out to be the most suitable environment for the bacterial colonies to multiply in large and do their magic.

Naming a few such media would include ceramic rings, Fluval zero-carb, Fluval ammonia remover, bio-media, bio-balls etc and many more. The Fluval bio-foam is a dual aquarium filter media which acts as both biological and mechanical filter media.

How is Biological Filter Media Used?

The underlying natural mechanism behind the sponge filter and under gravel filter is nothing but biological filtration. In case of power filter, canister filter, trickle filter, and fluidized sand beds, in order to initiate biological filtration, the respective filter media must be provided.

One must remember that the bacterial colony that is going to be the hero of the process of nitrification must first be large enough to handle huge nitrogenous waste outputs, else the entire motive behind biological filtration is defeated.

So, it is of utmost importance to stock the aquarium with mature bundles of biological filters. For that to happen, the entire aquarium must be cycled right before it is filled in with a variety of life.

The freshly cycled or matured tank would then be ready to be stocked with ammonia which is elementary so that the bacterial colonization gets initiated on the substrate without any delay or at times, the process may also need a catalyst like substance if the environmental conditions aren’t very ideal.

These catalysts are what is biologically termed as a starter culture. Once all these are done and dusted, the ammonia and nitrite levels in the tank are kept under the radar.

Delving a little more into the nitrification process by using biological filtration media, it is noticed that the ammonia levels drop first and leading to an increase in nitrite levels.

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This chemical transition is the result of the potential work of the huge colonies of bacteria that have been cultured on the substrate so carefully. The hyped up nitrite is then again converted to nitrate.

The colony again takes credit for this process. At a particular frame of time, ammonia and nitrite levels become absolutely zero. This marks the fact that biofiltration has been successfully achieved and also signals the re-stocking up the process of the aquarium.

How to Clean the Biological Aquarium Filter Media Correctly?

The filtration system must be checked from time to time to prevent excessive build-up of sludge which then makes the cleaning process more hectic. The huge quantity of water inside the fish tank must be emptied into a suitable containment.

This water must not be wasted, as they must be used to clean the biological filters in order to minimize the damage done to the well-developed colonies of microbial bacteria. The filter media must not be subjected to harsh cleaning processes. It must be gently rinsed by hand and the brown sludge must be removed carefully from the filter substrate.

Our prime motive is to clear the unwanted accumulation of sludge and other undesirable substances in the filter without causing even the slightest harm to the microorganisms

Chemical Filtration and Aquarium Filter 

Chemical Filtration and It’s Working

It is one of the very basic facts that light when transmitted through different aquarium filter media, gets dispersed depending on the refractive index of the medium. And this particular optical property of a medium is directly affected by the changes happening to its chemical composition.

So, when more organic compounds get dissolved in waters of the aquarium, there is a yellowish tint to the overall appearance of the tank caused by the dispersion of light through the contaminated water.

This tint prevents photosynthesis from happening normally as sunlight which is the prime ingredient for the process is obstructed from delivering the essential photons which trigger the process in the first place.

These happening directly affect the flora of the aquatic environment and also make it difficult for the corals to survive. Hence water in the tanks must be regularly changed at regular intervals so that the aquarium remains in a healthy state.

It would be best if the user makes it a habit to clean the tank from the very beginning, else it would become a total mess, literally. Despite nitrogenous wastes, there are also other types of compounds that contaminate and spoil the aura of the tank.

So, despite mere biological and mechanical filtration, there is a deep need for other effective filtration methods to clear out the other toxicities from the tank. Skimming might be another potential alternative.

It definitely does reduce dissolved organics but it is not capable of clearing out all such substances.

Chemical filtration – the all in all savior capable of clearing out all forms of impurities in the aquarium is the ideal filtration technique. This particular method is so efficient that whatever is left behind after skimming, biological filtration and water changes are all gone away totally.

This amount of huge positive outcome is possible because of the ideology of the technique which puts to use some well-known chemical constituents like organic compounds containing phosphates.

These phosphate-rich compounds constitute the major portion of the nutrients required for algal growth in the aquarium, indirectly leading to biological filtration through the process of nitration. These phosphate compounds also inhibit the growth of stony corals that disrupts the authentic look of the aquarium.

Which is the Best Chemical Aquarium Filter Media?

Activated carbon, which is nowadays being used for all sorts of purification purposes, ranging from the air conditioning to facial packs is obviously also used in aquarium tanks.

It has such versatile uses because of the ability to absorb harmful and unwanted chemicals and compounds. Apart from activated carbon, there are also other chemical filter media that is used to clear the tank of its contaminants and other harmful residues.

Fluval carbon, a very well-known chemical filter media in the industry is indeed a magical ingredient. It has superpowers that make liquid wastes like urine, dye extracts and other impurities go completely away from water without even leaving behind residues or traces in micro quantities.

This Fluval carbon not only removes the unwanted but also removes the effects left behind by those. These effects include the color changes, significant odor, reduced clarity of water and etc. Surprisingly, this material is also potentially able to remove heavy metal samples from the aquarium water.

Excessive phosphate, nitrite, and nitrate compounds are trapped by the Fluval clear max phosphate remover. This also enhances the odor of the water and provides crystal clear water that makes maintenance easier and also improves the look of the aquarium by several folds.

How is Chemical Aquarium Filter Used?

Carbon – the king of organics can very well be put to use in this area of requirement. A lot of different purposes can be served with this highly versatile element.

For a highly efficient chemical filtration rate, carbon should be subjected to a strong flow of water. By placing the carbon in an internal or an external power filter or in a reactor fed with water by a pump, the carbon piece can experience the flow of water over it.

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One other method is to place the carbon in an filter media bag and place this in a sump or a discreet place in the aquarium. This way, carbon will have water flowing over it but not forced through it which can be termed as the passive use of carbon.

Phosphate removers and most other chemical filtration media have to be used either in power filters or reactors with a strong flow of water through them to be effective. Fluidized reactors may also be employed in some cases when there is a demand to increase the efficiency of adsorption

Chemical Aquarium Filter Media Maintenance

Biological filtration involves the chemical transformation of toxic elements in the water into non-toxic compounds facilitated by the microbial colony cultured in the filter substrate.

As against this, the process of chemical filtration works by binding the undesirable substances to the filter media, thereby separating them from the rest of the components of water.

In this methodology, chemical processing of the substances into lesser complex substances does not happen. Hence, this puts us in the dire state of having to replace the media from to time. The chemical synthetic filter media is used for the desired task will stop binding stuff to it once it gets saturated.

This is the stage when we have to replace the filter media else, the contaminants would start getting accumulated in the tank, defeating the whole amount of filtering the filtrate did before it got saturated.

However, there is a problem with one specific substrate – carbon. Once it gets saturated, carbon starts dumping back the unwanted entities back into the aquarium.

So, if you are to use carbon filters, then you are involving yourself in a risky business. It sure does deliver exceptional positive outcomes, but if you forget to change the filters, then that would be the way you would have messed up your tank and your fate.

Cleaning and reusing the carbon media won’t work. No, it is not that kind of a filter. Instead, carbon filters demand replacement once every 3 months.

It is clever to use carbon in two or more aquarium filter media bags within their systems so that only a part of the carbon would need to be changed at any one time. This is also the exact idea used by hobbyists to cut down their costs at the same time, follow their hearts.


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That particular idea of using carbon in separate bags reduces the possibility of a sudden large increase in the adsorption capacity which might result in a rapid drop in dissolved organics. This could also be the consequence of all the carbon were changed at once.

But not all aquariums need a chemical filtration mechanism. So, it is always worth a lot of bucks to make sure if you really need something and then move forward with it. An efficient skimmer is more than enough but it would require partial water changes at regular intervals, else you would now what might happen.


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