DIY Fish Tank Filter

Fish tanks run the gamut from a simple bowl with a goldfish to a fancy saltwater aquarium filled with clownfish and tangs. And just as the kind of tank you have varies, the price of aquarium supplies can also vary drastically. But your aquarium doesn't have to break the bank. Certain parts, such as the aquarium filter, can be simply made using easy-to-find materials.

  1. Type of Filter

    • The easiest type of filter to build is an undergravel filter. With this type of filter, aquarium water is drawn through the tank's gravel at the bottom of the tank to filter. This type of filter acts as a biological or mechanical filter. For chemical filtration, you can mix activated charcoal with the gravel. Regular cleaning of this type of filter isn't required. Simply vacuum the gravel periodically. You may clean the filter when it is time to replace the carbon. Cleaning this type of filter requires you to drain the entire tank, take up, dismantle and clean the filter parts and replace the gravel.

    Process

    • For this type of filter, you will need a plastic 1- or 2-liter soda bottle, a plastic ice cream container, an air line, an air pump, aquarium gravel and activated charcoal. To build the filter, cut the soda bottle in half and scallop the rough edge of the top half of the bottle. Run the air line into the bottom of the plastic bottle and set into the ice cream container with the plastic bottle bottom side down. Attach the air hose to the air pump. Then fill the container and surround the bottle with gravel and carbon. You can hide the neck of the bottle with aquarium decorations including plastic rocks or plants.

    Mechanics

    • When the aquarium is full, the air hose releases air to bubble up to the surface. As the air bubbles rise, they draw water through the soda bottle and the surrounding gravel. Impurities in the water are trapped by the gravel and filtered out of the aquarium.