Making an Aquarium Filter

A fish tank is a balanced ecosystem that requires maintenance to keep its inhabitants healthy. If you have a home aquarium, then the chances are good that you've spent a lot of money on supplies to care for your fish. But you don't have to break the bank to keep your fish healthy. A number of items for your aquarium can be made at home using parts from local hardware and fish supply stores.

  1. Types of Filters

    • The type of filter you build will depend on the types of fish you keep. There are three basic types of filters: mechanical, biological and absorptive.

      Mechanical filters remove particles from the water. This keeps the particles from breaking down and polluting the water.

      Biological filters remove wastes from the water. This typically occurs in a porous environment such as a sponge kept in a glass tube.

      Absorptive filters trap specific materials from the water. An example of an absorptive filter is one made with activated carbon to remove toxins or a resin to remove ammonias or dyes.

    Filter Construction

    • A filter can be constructed in any number of ways. The most basic type of filter is a sponge filter. The sponge filter works by drawing water via bubble action through a sponge. The sponge initially acts as a mechanical filter. As beneficial bacteria grow on the sponge, it becomes a biological filter as well. A box filter sounds just like what it is, a box filled with filtration material. Water is drawn through the box, and its contents to filter out impurities. The filter might be biological if it is filled with a medium such as wool, absorptive if it is filled with a material such as carbon or both if filled with a combination of filtration materials.

    Filter Location

    • A filter might be placed inside or outside the tank. Biological and absorptive external canister filters can be made by filling lengths of PVC pipe with filtration materials and then circulating water through them with a pump and lengths of tubing. A mechanical under-gravel filter can be made by perforating a hose and placing it under aquarium gravel so that air bubbles up through the gravel. As the air bubbles up, it draws water through the gravel and traps particles there.