Filter Guide and Descriptions

Filter Guide

 

Sponge Filter

 

Description:

            A small box-shaped container that holds a sponge and sometimes a chemical purifier. It is often powered by an air stone and fits inside the aquarium.

 

Advantages:

            These filters are typically inexpensive, do not take up much space, and are easy to set up.

 

Disadvantages:

            Since these filters are so small, they are not practical for aquariums larger than ten gallons. Also, models that require chemical purifiers will need new activated carbon or zeolite every two weeks and the air stones that power the filters will have to be changed at least once a month. Lastly, changing all the filter media at once can easily upset the bacterial balance of the aquarium.

 

 

Mechanical Fast Filter

 
Description:
            These filters consist of a canister that can be filled with biological medium or chemical purifiers connected to a water pump. Additionally, the canister is sometimes  covered with sponge. This filter fits inside the aquarium.
 

Advantages:

            Since these filters use water pumps as opposed to air stones, they do not have as many items that need to be replaced. Since a water pump is used, these filters can be used in larger aquariums than sponge filters—up to 30 gallons. As with sponge filters, mechanical fast filters are simple to install and comparatively inexpensive.

 

Disadvantages:

            Because the surface area of the canister is relatively small, these filters can clog easily and the performance of the filter will diminish proportionately. Types that require chemical purifiers will need replacement purifiers every two weeks. Furthermore, care must be taken to not remove all the filter media at the same time or the beneficial bacteria populations will drop.

 

 

Undergravel Filter (UGF)

 
Description:

            A grid that is placed under the gravel with one or more uplift tubes that rise out of it. Air stones or powerhead water pumps are used to pull water through the grid and up through the uplift tubes. Models that use air stones often make use of carbon or zeolite cartridges that fit inside the elbow that connects the air line with the uplift tube. UGFs can be made for almost any size of aquarium.

 

Advantages:

            The undergravel filter usually provides a large surface area of medium and thus does not easily clog. Also, when used with powerheads instead of air stones, the potential of the filter improves dramatically. Using a powerhead cuts down on the cost of maintaining the filter as you will not need cartridges or air stones.

 

Disadvantages:

            While the initial expense is not too high when powered by air stones, undergravel filters that utilize one or more powerheads can have a high start-up cost. On the other hand, air stone-powered UGFs have a high maintenance cost due to the air stones and cartridges they use. Furthermore, undergravel filters are very much biological filters and thus require a decent amount of maturation time and a good understanding of biological processes on the part of the owner.

 

 

Power Filter (HOB)

 
Description:

            A box with an internal water pump that hangs on the outside of the aquarium and pushes the water through one or more filter inserts and often uses activated carbon. Power filters are available for most common aquarium sizes. Power filters are often called HOB’s as an acronym for Hang-On Box filter.

 

Advantages:

            These filters are relatively simple in design and function. They are also very efficient due to the water pump they possess. These filters are ideal for beginners because they can handle many of the errors a novice might make and are easy to operate.

 

Disadvantages:

            HOB filters have an Achilles’ heel: if you change an insert, you remove all of the beneficial bacteria at the same time. This means that changing the cartridge(s) on a HOB is a very risky venture in that the filter will take several weeks before it is running at full capacity again. To remedy this situation, some aquarists either place large amounts of semi-porous substances in the main tank to act as a home for the bacteria (making a cartridge change less traumatic) or simply reduce the number of fish that they keep so that the bacteria living in the main tank can handle the waste load while the filter population is re-growing. Another alternative is to “seed” the filter cartridges by placing them behind the cartridge they will eventually replace. Still other aquarists go another route and simply omit changing the cartridge. This last group of aquarists does not use activated carbon and simply rinse out the cartridges with luke-warm water when they become clogged. Lastly, the intake tube of HOB's is infamous for sucking up small fish or tearing part of a fish's body apart (fancy goldfish have had some of their face extensions sucked off by HOB's).

 

 

Canister Filter

 
Description:

            A large canister with a water pump connected to the aquarium by a system of hoses. These filters may use biological mediums like ceramic tubes and sponge, chemical purifiers such as activated carbon, or a combination of biological mediums and chemical purifiers. Only practical for medium and large aquariums (50+ gallons).

 

Advantages:

            Since it is not directly connected to the aquarium, it is easy to hide and disguise. Also, models that do not require chemical purifiers can go more than a month without cleaning.

 

Disadvantages:

            Canister filters can be cumbersome because of their many hoses, can be difficult to clean,  are expensive, and have a comparatively small turnover. In addition, models that use chemical purifiers will need replacement activated carbon or zeolite every couple of weeks. Like other filters, care must be taken when removing the filter media. Removing too much can upset the bacterial balance.

 

 

Trickle Filter

 
Description:

            Basically a canister filter that introduces more oxygen into the system by causing the water to flow through a spillway before entering the canister. As with canister filters, these filters are not practical for small aquariums.

 

Advantages:

            More efficient than canister filters, trickle filters are typically the only suitable option for very large aquariums and, due to their increased oxygen content, are especially beneficial to brackish water fish as they do not compete as much with the fish for oxygen.

 

Disadvantages:

            The trickle filter is expensive and complicated. Best left to the experienced aquarist.

 

 

Diatom Filter

 

Description:

            A large canister with a water pump that hangs on the outside of the aquarium. Uses a circular fiber floss or micro-fiber insert.

 

Advantages:

            Rids water of contaminants quickly.

 

Disadvantages:

            As this filter can clog easily, it is not practical as the primary filter. It is also expensive.

 

 

Plenum

 
Description:

            A grid that is placed beneath the aquarium substrate. It works by allowing a small amount of water to flow through the substrate in such a way that wastes are broken down into nitrate and a fair amount of nitrate is denitrified. As this filter has no power source of its own, it must be combined with powerful circulation pumps that provide a turnover of at least 10 cycles per hour. The plenum is essentially a device that encourages residual flow.

 

Advantages:

            A very simple design that is both easy to maintain and comparatively inexpensive.

 

Disadvantages:

            The plenum is a filter system that takes time to mature and requires the use of powerful water pumps.

 

 

 

UV Sterilizer

 
Description:

            A tube containing a UV bulb or bulbs through which aquarium water is forced. It is designed to kill pathogens and algae by exposing them to deadly levels of ultraviolet light.

 

Advantages:

            Kills a great number of water born diseases and helps the water from becoming clouded due to bacteria or algae.

 

Disadvantages:

            As exposing the fish to specific wavelengths of UV light can kill them, UV sterilizers do not shine directly into the aquarium. This means that disease organisms can still exist in the aquarium, just not in the UV sterilizer.

 

 

General Filter Guidelines

 

·         Combining filters that operate at different levels is not suggested as they may compete with each other (the one with the higher GPH usually becomes clogged).
·         Clean filters that become clogged as soon as possible to prevent nitrogen compound build-up, but never use hot water or chemicals as doing such will kill the beneficial bacteria. Also remember to never remove all of the filter media at one time.
·         Look for filters that have a high turnover rate as these are often the most efficient ones.
·         Choosing filters that do not use chemical purifiers cuts maintenance costs but will not significantly decrease biological load potential if the tank is properly cycled.
·         Look for filters that have at least a one year warranty to avoid replacing the filter too often.
·         Shop around and look at all your possibilities. This way, you have a better chance of finding a filter that fits both your budget and aquarium stocking goals.
·         It is suggested that you buy more filtration than what is needed for your aquarium. Specifically, having two filters of equal size can be advantageous in that if one fails, the other will still work and give the aquarist time to buy a replacement filter.
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