| One of the most important pieces of equipment | | | | external (hang over the back) power filter, and |
| that you need when setting up a freshwater fish | | | | canister filters. Roughly speaking the list is in order |
| tank is the filter. With so many aquarium filter | | | | of cost and effective tank size. The sponge and |
| systems available today, the beginner may get | | | | the box filters rely on an airstone to power them |
| confused as to what they actually need. A good | | | | while the undergravel can use an airstone and/or |
| filter must provide multiple levels of filtration and | | | | a powerhead. The internal, external, and canister |
| be appropriately sized for the tank that it will be | | | | filters all use a power motor of some sort. |
| used in. Beyond that, other considerations depend | | | | When choosing a filter, the size of the tank as |
| on aesthetics and budget. | | | | well as the number and type of fish that are |
| Any worthwhile aquarium filter will provide | | | | going to be kept in it (also known as bioload) need |
| mechanical, chemical, and biological filtration in the | | | | to be considered. In smaller tanks, such as a 5-15 |
| aquarium. Mechanical refers to the filtration of | | | | gallon tank, a simple box or sponge filter will often |
| physical particles such as fish waste, excess food, | | | | do the trick. An undergravel filter is suitable for |
| dead plant material, etc. Chemical filtration is | | | | 10-30 gallon tanks and the internal power filter |
| concerned with the removal of unwanted | | | | works best for the 15-40 gallon range. When it |
| chemicals in the fish tank water, such as ammonia | | | | comes to the external power filters and the |
| and excess nitrites that can build up and prove | | | | canisters, they can work for tanks as small as |
| toxic to the fish if not filtered out. | | | | 10-15 gallons, but they are the filter choice for the |
| The third part, biological filtration, is accomplished | | | | bigger tanks because they can be scaled up in |
| by beneficial bacteria that live in the filter and in | | | | size to handle just about any sized aquarium. |
| the substrate of the tank. This is often | | | | Regardless of how effective the filter is, periodic |
| overlooked, but is extremely important. These | | | | water changes and gravel cleaning is still a |
| bacteria are the main driver of the nitrogen cycle | | | | necessity. No filter is powerful and efficient |
| which is the process by which fish waste and | | | | enough on its own to take care of all the needs |
| food is broken down by the bacteria and turned | | | | of an aquarium, so bear that in mind and don't |
| into usable nitrate for the plants in the aquarium. | | | | think that bigger is better, either. When in doubt, |
| All effective filter systems employ all three of the | | | | ask questions at the fish store and read the |
| filtration processes. | | | | information on the filter boxes, and making the |
| There are a few basic filter types that are | | | | right choice should not be difficult. Buy the right |
| available for use. They include the sponge filter, | | | | size filter for the tank and do water changes, and |
| box filter, undergravel filter, internal power filter, | | | | your fish will stay happy and healthy! |