Instructions
Understand the two types of filters. Biological filters don't need maintenance--since you don't want to disturb the good bacteria--but they do require oxygen. Mechanical or chemical filters need maintenance. You need to change the filters every two to four weeks.
Select the kind of filter you want to use. You can get canister filters, corner filters, fluidized bed filters, power filters, sponge filters and wet/dry filters.
Buy a canister filter when you have messy eaters in your tank. This type is very powerful and you can use it inside or outside the aquarium, but you have to maintain it often. The best place to use it is in a medium or large aquarium. Maintenance is more difficult if you use the canister filter inside the tank, since you have to reach into your tank and retrieve it to clean it.
Find a corner filter when you have sick fish. This is best for this situation since it is inexpensive and it works as a biological and mechanical filter.
Set up fluidized bed filters when you have another filter to provide the mechanical or chemical filtration. This also applies to sponge filters that are also good to use if you have baby fish in your tank. These are easy to maintain which is a plus for them.
Locate a power filter when you are setting up a small aquarium. They are inexpensive, don't take up space in your aquarium since they hang on the back and are the most commonly used filters.
Use a wet/dry filters when you want one filter to take care of all your needs. The downside to using the wet/dry filter is that it can only be a biological or mechanical filter at any time--this depends on the way you set it up.
How to Maintain the Filter for Saltwater and Freshwater Aquariums
No matter whether you have a saltwater or freshwater aquarium, learning to maintain your filter is a high priority. Filters come in two types--biological and mechanical or chemical filters. Biological filters keep the fish healthy and mechanical filters keep the water clean.