There are many different types of filter systems, and if you are taking care of only one aquarium, it would make sense to search for the filter system best suited to your maintenance practices. For example, when we had only six aquariums, we used the outside box filter with its impeller motor and removable filter sheet. This system was appealing because it seemed less labor intensive than inside corner filters. However, the outside filter boxes are expensive, you throw out your bacteria colony when you throw out the filter media, the impeller motor often halts when the power goes off and on again, and they are a pain to clean. They should be cleaned regularly.
The different filter types available to the hobbyist are described and evaluated in books and general fish hobbyist sites on the Internet. We will focus on the corner or box filter shown on the previous page and another type of filter used by guppy breeders, the sponge filter, shown at right.
Often a box filter and a sponge filter are used in combination. The two air streams in the tank create a great deal of agitation at the surface and the water circulation below. This facilitates the exchange of oxygen and carbon dioxide at the surface. And the sponge provides a substrate upon which colonies of bacteria can grow. You only clean one filter at a time, leaving the other until next time. This ensures at least one filter system is always fully functioning as a bacterial colony at any given time.
Floss and Marbles