Just Say No to Abuse Declaring War on Terrorism. In this article, I will discuss some of the freshwater aquarium filtration systems.
Freshwater filtration is just as complex as that for saltwater systems.
It is the water maintainence that differs. The basic job of a filtration system is to promote the nitrogen cycle of the aquarium, and to remove debris and other particles from the aquarium. Undergravel filters operate by using an uplift tube to draw aquarium water through a filter plate in the bottom of the aquarium. For a diagram of this type of filter, take a look at this page. These filters use biological filtration to keep ammonia and nitrite levels low in the aquarium.