This is a follow up from my earlier post “Choosing The Right Fish Tank Filters“.

Defining Undergravel Fish Tank Filters

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In General undergravel fish tank filters are a type of filter where water flows through a layer of gravel which acts as the primary filtration media. The undergravel fish tank filters system consists of a plastic grate which is placed at the bottom of the tank, tubes that direct the water through the filter and a power head or pump.

How Do Undergravel Fish Tank Filters Function?

The plastic grate lies at the base of the tank. A layer of gravel is placed on top of the plastic grate. This separates the water above the gravel from a layer of clean water below the plastic grate. Water is drawn through the gravel layer, which acts as a biological and mechanical filter. The flow of water through the gravel is achieved with the pump which has an inlet below the plastic grate, sucking the water below through plastic tubes that will then spill the clean filtered water from the top of the tank.

As the tubes suck out the water from below the plastic grate, this forces the water above to be drawn through the gravel layer where, through mechanical filtration, sediments, excess food and waste is trapped. The gravel layer also performs basic biological filtration by trapping bacteria. The water that results from this filtration will be clean and will follow the cycle, flowing through the tubes and to the top of the tank.

Maintenance Requirements For Undergravel Fish Tank Filters

Because your filter media is the gravel, you will never have to replace it. However, as the particles are trapped by the gravel it will need to be cleaned. The frequency of cleaning that you need to do varies, depending on how many fish you have in the tank and how frequent you feed the fish. If you have a large tank, it would be easier to use an aquarium vacuum to remove the sediments from the top layer of the gravel. If your tank is small, you may as well just wash the gravel when it starts to get slimy.

As the sediments build up above the gravel it will eventually block the flow of water through. Sediments would also be forced through due to the suction of the pumps. This will create a lower water quality in the tank. So it is important to clean the gravel as the sediments build up.

In Summary…

Undergravel fish tank filters have received some bad press from people who claim that it does not provide sufficient filtration as well as a build up of waste at the bottom of the tank. But undergravel filters are good for beginner fish tanks that do not contain many fish, is not too large and the fish you are breeding are not overly sensitive. It is relatively cheap compared to canister filters and power filters. It requires very little maintenance and is very easy to clean. Though does not provide chemical filtration, if what you have is just a basic fish tank than this would be a good fish tank filter to start out with.

Continues in the next post: Benefits Of Canister Fish Tank Filters

This post is a follow up from my previous post “Advantages And Disadvantages Of Different Fish Tank Filters“.

What Are Power Fish Tank Filters?

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Power filters are a popular type of fish tank filters used today. One major advantage of power filters is that it is able to be used along with any filtration system. A power filter generally provides chemical, biological and even mechanical filtration. They run on electricity and comes with an internal motor. Power filters come in a number of sizes and another determining factor for the choice of filter to select is power consumption. Most power filters are equip with different built-in flow adjusters and multi-directional outlets that can be suited to meet the specific needs of various aquariums.

Usually these fish tank filters hang on the back of the aquarium and suck in water through an inlet tube which is placed inside the aquarium. The water then flows through a series of filtration pads and filter media. The filtration pads act as chemical filters, having contained within them charcoal that also traps debris. The filter media acts as biological filters. After passing through these two filters, the clean water is returned back into the fish tank.

How Do Power Fish Tank Filters Work?

Power fish tank filters are powered by a powerhead which is a piece of equipment located either inside or on top of the power filter. It consists of an electric motor which drive a pump and is sealed in hard plastic. It is this pump that sucks in the water, forces it through the fish tank filters and returns the clean water back into the tank. The speed and force of the water can be adjusted by regulating the airflow into the filter through adjustable valves. This is a very useful function especially when using power filters in small tanks or when there are small fish present, when having too strong currents into the tanks might be detremental to the fish’s health. Regulating the water flow will also allow its direction to be directed into a specific area of your fish tank.

More Fish Tank Filters Advantages

Another advantage of using a power filter is that it is able to draw water faster than most conventional air pumps. This allows a greater volume of water to be filtered in a shorter period of time. This function is very useful when you have a tank that is very cloudy and need to urgently clear up the water.

While it does need minimal cleaning, there is some maintenance that needs to be done. Generally, what needs regular cleaning every week of fortnight is the filtration pad that will get clogged from the excess food, fish waste and sediments that is sucked into the fish tank filters.

Continues in the next article:  What Are Undergravel Fish Tank Filters?

 This is a follow up from my earlier post “Choosing The Right Fish Tank Filters“.

All Fish Tank Filters Are Not Created Equal

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Setting up a good fish tank filter will make a great difference to the quality of life of your fish and the enjoyment you get from this great hobby. But because there are so many different types of filters to choose from, you might be wondering which is the right aquarium filter for you. While it is true that the ideal filter to get is an external or canister filter, you should also take budget into consideration. Below, I will be explaining the advantages and disadvantages of the more popular types of fish tank filters.

Corner Fish Tank Filters

This is a smaller plastic box filter which sits on the bottom of the fish tank, above the gravel in a corner of the fish tank. The box contains layers of floss and charcoal through which water is suck through and filter before exiting from the top. The advantage of the Corner Filter is that it is dirt cheap. However, they are not very efficient and would not be able to keep the water clear for long. And the floss and charcoals needs to be clean frequently.

Sponge Fish Tank Filters

Water is filtered through a couple of layers of sponge. While it is slightly better than a Corner Filter and just as cheap, it too is not very efficient and needs frequent cleaning. The advantage is that it does not stir up the water too hard and is ideal for fry tanks and quarantine tanks.

Undergravel Fish Tank FiltersA good low budget filter which does not generate too strong currents in your tank. Once the undergravel fish tank filter is allowed to function for a while, it does quite a good job in maintaining the clarity of the water. Dirty water is forced to flow down the tank through the gravel where is trapped in the empty space beneathe the filter’s plastic grate. It is the gravel that does most of the filtration so if your fish tank water is cloudy, it will take a couple of days to clear up properly. It will also require an additional pump for sucking the water through the gravel.

External Side Fish Tank Filters

The filter sits in a box that is hung at the side of the fish tank and does all its filtration outside the tank. Water is suck through a tube which travels through a series of filters that performs biological, mechanical and chemical filtration before it flows into a through that spills back the clean water from the top. The advantage of using this filter is that it only needs a weekly or fortnightly cleaning and clears up cloudy water pretty quick. But because of the strength of its suction, it does have the tendency to suck small fish so you should not use this if your fish are too small.

Canister Fish Tank Filters

The Ferrari of fish tank filters, the Canister filter is the ideal filter to use if you have the budget and are serious about your hobby. They need very little maintenance and does an excellent job at keeping your fish tank water clear and pristine. They are the ideal fish tank filter for busy people who just cannot find the time to clean their fish tanks. They are however expensive and are a little strong so you should only consider a Canister Fish Tank Filter if you have a nice large fish tank.

Read the next Fish Tank Filters article: Power Fish Tank Filters Defined

Are Fish Tank Filters Really That Important?

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Other than a heater, fish tank filters are probably the most important element in an aquarium set up. Without using proper fish tank filters, the water in your tank will be stagnant, cloudy and make it almost impossible for your fish to live well.

In general, fish tank filters come in two main categories; external and internal. Both these fish tank filters can be used for either salt water or fresh water tanks.

Internal Fish Tank Filters

Internal fish tank filters come in two basic types. The first type of internal filter, the undergravel filter, is usually used in fresh water fish tanks. Undergravel filters consist of a raised plastic grate which lies on the base of the aquarium with gravel placed over it as base material. Clear vertical tubes are attached to holes in the filter and these have either a power head which sits on top or sometimes a bubbler inserted in them. The gravel acts as a filter as water is forced to flow through it, collecting sediments, excess food and fish waste and pumping clear water back up the tube into the tank.

The other type of internal filter is similar to a sump tank that lies just below the main tank, used mainly for salt water aquariums. This filtration system has an internal tube which flows water into the sump, from which it is then pumped through a series of filters that traps all the waste material and even bad bacteria. The water that is filtered is then pumped back into the tank from the top, providing not only filtration but also excellent circulation. This type of filter can be a little expensive and noisy but it is a lot better than the gravel type. However, if you are considering it, bear in mind that you would have to custom build your fish tank to support the sump base. Almost all ready made fish tanks are generally not capable of this type of filtration system.

External Fish Tank Filters

External fish tank filters are the best type of filtration system to use if you are able to afford it. Because the filtering happens outside of the aquarium, it keeps the clean filtered water separated from the unfiltered water before it is returned pristine to the tank. Generally, external filters have a few long hoses connected to them, providing separate supply and return routes. Though it is the most effective filtration system, it is however the most expensive.

Local pet stores generally carrying the cheaper types of filters, mainly the fish tank undergravel filter. If you’re planning to get the more expensive version which are generally more effective, you would have to look for the filter of your choice at a specialized fish store. If you do decide on investing for a better fish tank filter, it would be advisable to install an external filter. It would initially cost more but in the long run, having an external filter would save you on maintenance costs and provide your fish with a healthy environment to live longer and even breed.

Recommended article:

Advantages And Disadvantages Of Different Fish Tank Filters