top of page

Importance of Filtration and Why? Types to consider

Updated: Feb 1, 2023

Importance of  filtration

The heart of a successful aquarium is the filtration system that goes into it. If you neglect the proper filtration system for the Aquarium then it’s a recipe for a disaster.

Why filtration?

Man Thinking Why Filtration
Man thinking Why?

An Aquarium is a closed environment, unlike the wild where the water flows gradually. There is constant clean water in the streams, and rivers and the filtration in the wild is natural. The fish gets adapted to such natural filtration. Hardly you will find the water stagnant. In the wild, due to the constant movement water is well oxygenated. The fish thrive in such an environment. The conditioning of an Aquarium depends upon us. We need to give its habitants a clean environment.

Fish pooh and respiration, uneaten food, and dead leaves contaminate the water. This rise in contamination if unchecked results in Ammonia, nitrite, and nitrate in the tank resulting in the death of its inhabitants.

Filtration plays a greater role to achieve a well-managed balanced aquarium. A good filtration system should have 3 things to be effective Mechanical, biological, and Chemical.

Mechanical Filteration

Mechanical Filtration
Mechanical filtration

Many beginners think that mechanical filtration is the only filtration to consider, but that is not true in most cases especially when the Aquarium is bigger. Mechanical filtration removes particulate material from the water column. Free-floating debris and feces are first trapped by the mechanical filter. These are layers in form of mesh. Then you have a slightly thinner kind of mesh The water is passed through these layers and the debris is trapped. These free-flowing debris must be trapped otherwise the debris will convert into a harmful substance. This is just one part of effective filtration. Mechanical filtration will not remove or convert ammonia, nitrite, and nitrate. Mechanical filters also need to be washed every month and need to be changed at least every four months to be more effective. It all depends upon the bio-load in an Aquarium. Don’t let the debris clog the filter. If it's clogged the system will throw up the dirt back into the Aquarium. We need to understand the other forms of filtration too that is Biological and Chemical.

Biological Filteration

Seachem Matrix
Seachem Matrix

A biological filter is a very important filter, especially in creating nitrifying good bacteria. There are well-known biological filtration media available in the market such as Seachem Matrix, Biohome bio gravel, or even Biohome Ultimate. Some use even volcanic chips, porous ceramic rings, and bio balls, in the system to create a colony of good bacteria. The greater the surface area of these media the better it is for the bacteria to reside. The more beneficial bacteria that reside, the better it is for the aquarium to thrive. The good nitrifying bacteria will convert the ammonia into nitrite and finally into harmless nitrate. Most condition their water by introducing good ready nitrifying bacteria into the tank. This helps in stabilizing the tank quickly by fast-forwarding the process of the nitrogen cycle. Seachem Stability, easy life – easy start, and Quick start from API are some of the products available in the Indian market to jump-start the process of the nitrogen cycle by introducing good aerobic, anaerobic bacteria. There are other local brands too. My favorite is Seachem Stability. A very well-established product in the world. We use it quite often in our tanks at our store. The Advantage of Stability is when there is more bio load in the Aquarium the bacteria from stability will not die out as compared with other companies products. Stability thrives in such conditions. Stability is a blend of anaerobic, aerobic, and facultative bacteria that facilitates the breakdown of waste organics. ammonia nitrite and nitrate. There is a lot of scientific research gone into the product.

We have widely used matrix as our biological media as our first choice for its surface area and its support of aerobic and anaerobic bacteria. You need not change it. The shelf life is a very long time. You need to change it only if it turns brown. Just give it a rinse by using the tank water when you are doing the maintenance of the filters.

Chemical Filtration

This is normally the last layer in the filtration where the water needs to be passed through before entering the water. Chemical filtration is used to remove and dissolve waste from the water. The dissolved waste is considered the hardest to remove, chemical filtration polishes the water that enters the tank through the outlet of the filter, mostly achieved by activated charcoal or you can use Chemipure, Chemipure Elite, or Seachem Purigen. We have used both the products of Boyd enterprises that is Chemipure and Chemipure Elite. We have found Chemipure Elite very effective on our African Cichlid tank which was a 5-foot tank. Within 12 days we had a clear tank. We have also used Chemipure Green for the planted tank because of its advantages, and we have found it to be very effective. It does not remove any micro and macronutrients.

It gives a clear tank for the light to penetrate the tank.

Tip:- When Using Ultra violet rays into the tank. Please do not use it for a long time( not more than 24 hours). Any exposure for a pro-long period to the ultra-violet lights will kill the beneficial bacteria.

Since we now understand the types of filtration required, now let's understand the type of filters in the market. I have explained 3 types as they are commonly used by aquarists.

A power filter sometimes called a “Hang-on-back” filter

According to our experience, a good Power Filter is an excellent option especially when you have a smaller tank of up to 200 liters. There are various "Hang-on-back" filters in the market from various companies to be considered for different volumes of water in the tank. They do not disturb the water much and there is much-needed oxygen in the tank. It's very easy to set up the Power filter, The compartment of the power filter is situated at the back of the tank so the name goes “Hang-on-back” filter. The water is taken in from a suction tube attached to the filter into the tank then the water enters the compartment at the back of the tank. The water is passed through the mechanical filter at the first stage which traps the debris which is then passed through the biological filter which is the media holding the beneficial bacteria and finally its flows through chemical filters which are activated carbon. Clean water flows back into the tank from the outlet.

Case Study:

We had established a tank of 80 litres for a client two years ago. It was a simple planted tank using Tropica as our main soil also because it is backed by nutrients. We also introduced bacteria from Stability for rapid stabilization of the filter and the tank. The client wanted a good filter. So we selected for the client Seachem Tidal35 (hang on back). Seachem Tidal series are most of the active hang on the filter with mechanical filter, a biological filter that can be used in their compartment. There is enough room for all types of filter media including the chemical filter. The entire ecosystem thrived and the plants grew well and the fish we selected were the Tetras. Why seachem Tidal 35? Because it came with the matrix media as our first choice for biological filtration, it was easy to maintain, and it had a surface skimmer, maintenance alert, and flow speed adjusting knob. Seachem Tidal filters have been used across the world for their many advantages. We used it in our project because of its ease of Maintenance.

Tip: Plants also act as an excellent source of filtration. They remove the ammonia from the tank. Plants act as a superb place to create nitrifying bacteria. It does not mean that your first task should be a planted tank.

Canister Filter

Fluval canister 207 re-engineered
Inside of Fluval canister 207

If you have a tank of more than 200 liters, It's worth taking a shot at the canister. They come in different capacities meant for the various volume of water. Consider a quiet canister and energy saving. Some people resort to buying cheap canister available in the market only to be disappointed that it makes noise and gets clogged faster. Even their primming is not easy. The canister has all the compartments in it, some come in trays to keep your filter media in it like the budget canister SunSun 304B. it came with an Ultraviolet option. I felt it was just a gimmick, not much of use for me. Some have technical superiority over others but are expensive, we call them cost-effective one-time investments such as the Fluval range of canisters. If you have larger tanks of 1000 liters/1500 liters consider having Fx4/Fx6, It does it work effectively and quietly. In India the price is too high, you can be lucky if you can bring these from well-reputed stores abroad since they have their discounts regularly. I have used SunSun 304B, Within a year I had to discard it and use it as storage because my machine konked off. Primming was getting difficult. The machine started getting clogged way too often and one fine day it just stopped resulting in the death of some of my African Cichlids in my absence. My point emphasizing the sun sun 304b case was that a budget canister might not work if the bio-load is too high in the tank. It requires frequent maintenance.

Eheim Canister
EHEIM 2217

There is an Eheim canister that I had used and was found to be a cost-effective solution in my 400 liters tank. I used Eheim 2217 and found it suitable for my tank, also used 350classic from Eheim on the planted tank. We strongly recommend either Fluval or Eheim canister. Depending on your budget you can consider either of them. As per the market feedback, Dophin c1600 is also a good option in India.

Tip: Always check the pump performance that is Gal/per hour. It has to be 4 times the volume of the water in the tank. Always buy a canister that can offer you a warranty of somewhat. But with various don’t’s in their warranty terms & conditions, I don’t know whether it works.

Sponge filter (Internal Filter)

xy-380 super biochemical sponge filter
XY-380 sponge biochemical filter (good Quality)

There are many internal filters like sponge filters, some internal filters are attached to the glass with their motor inbuilt. Some need to be attached to a motor outside like the Sponge filter. Internal Filters mostly come with the mechanical media. They provide also good surface agitation which helps in oxygenation. If the tank is less than 100 liters it's worth considering an internal filter. Always consider an internal filter that has an adequate flow (not strong to make the fish float) and not too less, it should cover all the parts of the aquarium. Most Shopkeepers and breeders use the sponge filter. Great place to create colonies of bacteria. Cheap and the best for breeding. The fries do not get into the filter and disappear. A good place for nitrifying bacteria to establish a colony. It gets dirty fast. You just need to rinse it into the tank water. It's not suitable for big tanks but some aquarists swear by this filter. They also help in the oxygenation of the tank. I use it at my store in some of my tanks. The XY series is a good-quality sponge filter. SOBO and SunSun brands for internal filters can be considered a good option. Some good corner-based filters are also available from SunSun JP094 where speed can be adjusted and the flow direction too can be adjusted. Also can be used in a small planted tank. Most of the internal filters have only mechanical filtration. Some internal sponge filters also hold some bio-media (biological media) as shown in the image below. Sponge filters can also be used in a hospital tank.

Aquarium Sponge biological filter
Aquarium Sponge biological filter

There are other filters the age-old filter like the Under Gravel Filter, the Diatomic filter which is used temporarily to remove diatomic algae, and some premium filters that come with a pre-filter in-built into the canister like the OASE.

As technology advances companies like Fluval, Seachem, Eheim, and the new entrant in the Indian Market, OASE has wonderful features. This article was to make you aware of what to buy since many products are made available. But, scattered information is out there and many times the aquarists are confused about what exactly to buy for their aquarium. Filtration is a vital cog in a success of an aquarium.

Summary Tip:-

Always check the volume of the water in the tank and the pump performance of the filter which is gallons/per hour. for example if the Volume of the water in an Aquarium is 50 liters. The filter should be able to take in the volume and should be able to pump the water at least 4 times the volume of the water in the tank that we say as gallon/per hour.

In this case, 50*4 = 200 gallons hour to be effective.

Some canisters come with media. Consider this as the media can save you some money.

Also, consider the wattage used by the filters. It should not burn a hole in the pockets in the long run.

Lastly, Do not consider filters that make noise and become a nuisance in the room.

Please note that we are not promoting any brand nor they have paid us to do a write-up. Wish they had drawn a fat check. lol, We have sighted their brands as we have experienced and used them. And some are written on market feedback in India.

For Inspirational Topic

For Inspirational Video

For Aquarium Needs you can log on to

To Subscribe for Updates and newsletters. Our Subscribers get discounts and much more benefits. newsletters. Be our Subscriber. Now !!! Why pay more somewhere, when you can pay less at aquafishcare.

Seachem Products Booking are Open, please WhatsApp 9821798612. Book ASAP. Limited Products


Author :- Sunil Dcosta for


100 views0 comments

Recent Posts

See All


Rated 0 out of 5 stars.
No ratings yet

Add a rating
dog photo thai.jpg
bottom of page