I Like Undergravel Fish Tank Filters

This is a follow up of a previous post titled “What Are Undergravel Fish Tank Filters?“.

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The one thing that with guarantee healthy and vibrant fish above everything else is crystal clear water in your aquarium. And only fish tank filters are able to do this for you. Fish tank filters are the most important tool in an aquarium and together with a fish tank heater, forms a perfect system that is capable of providing your fish with a similar environment from where they originated.

One filter that has stood the test of time is the undergravel fish tank filters. Though it is mostly used by beginners to fish breeding, it is able to provide water filtration that is reliable and efficient comparable to any other filter.

How Undergravel Fish Tank Filters Function

The filter functions by drawing water through a layer of gravel. The gravel rests on a slightly raised platform away from the base of the tank. This creates a division between the unfiltered water at the top and a layer of clean water at the bottom, with the gravel acting as a filter. It performs mechanical filtration by trapping large debris, food excess and waste and beneficial bacteria in the gravel layer also perform biological filtration.

8 Reasons Why Undergravel Fish Tank Filters Are Great

Here are 8 reasons why I consider undergravel fish tank filters to be among the best types of filters on sale today.

Reason #1: It Regulates Temperature

The undergravel filter sucks in water from the bottom of the fish tank and pumps it back from the top. This will mix the water up continuosly, as long as you do not turn off the filter. This circulation of water causes every area of the fish tank to experience the same temperature.  Because of this water circulation, every part of the aquarium maintains the same temperature. Additionally, you could also place your fish tank filters beside the lift tubes, which will warm the water as it rises and provide excellent temperature balance in your fish tank.

Reason #2: Water Aeration

As the filtered water rises from the bottom through the lift tubes, it will come in contact with outside air. This aerates the water even better than the bubbles in the tank could.

Reason #3: Excellent Mechanical Filtration

In this system it is the gravel that acts as the filter media, trapping large debris, food waste and excess perfectly.

Reason #4: A Good Biological Filter

When you have allowed the gravel to age, usually within six weeks without help, beneficial bacteria will colonizes the gravel. These Organisms reduce organic proteins into nitrate which can simply be discarded each time you change the tank water. The nitrate is also a substance consumed by aquatic plant life.

Reason #5: It Is Capable Of Chemical Filtration

This is one factor ignored by most people, that undergravel filters are capable of being fit with cartridges that perform chemical filtration. Inside these cartridges usually are activated carbon that helps remove heavy metal, complex proteins, odor, color and even chemical treatment.

Reason #6: A Bigger Capacity For Waste

Because it is the entire area of gravel at the base of the tank that actually filters the water, undergravel fish tank filters can hold the most waste before it needs to be cleaned.

Reason #7: Easy To Maintain

Over time, the gravel will begin to accumulate a layer of muck thatneeds to be cleaned. if it isn’t then it will begin to choke the filtration system by not allowing water to pass through. How do you clean it? By simplying vacuuming up the muck. A simple method of doing this is by using a rubber hose as a siphon to suck up the muck when you plan to do your water change.

Reason #8: Inexpensive

Isn’t that really the main draw for most of us? Buying an entire set is usually cheaper than other reliable filtration systems. The filter media is the gravel and never needs to be replaced. The parts are quite sturdy and even if you need to replace a part, they are cheap.

There you go. 8 reasons to convince you how good the undergravel fish tank filters are.

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 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