DIY Undergravel Filter

Among aquarium enthusiasts, undergravel filters are a line that divides camps. Some aquarium lovers think they are great, while others can't stand them. Undergravel filters have their advantages and drawbacks. However, they are inexpensive and easy to install and clean. Best of all, you can make your own filter easily.

  1. Undergravel Filter Principles

    • An undergravel filter is a filter that provides both biological and mechanical filtration, while at the same time oxygenating the water. An undergravel filter pumps air under the gravel of the aquarium. As the air moves upward, it draws water down into the gravel. The gravel collects and holds organic matter, algae, dirt and impurities, keeping them out of the water itself. This also fosters colonies of healthy bacteria that break down the matter. The gravel and filter both need to be cleaned frequently to keep the tank in good working order. If you have a messy type of fish, such as a goldfish, cleaning will need to be performed even more frequently.

    Materials

    • A good undergravel filter can be constructed from a network of PVC electrical conduit. The exact number and length of tubes and connectors will be determined by the size of your fish tank. You will also need an air line and a pump to pump air into the fish tank. You will also need a drill and a utility knife for cutting the conduit.

    Process

    • To construct your undergravel filter, cut start with 5-6 tubes of conduit. Use your connectors to build a network of conduit pipes that has tubes every 15-20 centimeters apart from one another. Glue the pipes into the connectors and let the glue dry before proceeding. Next cut grooves in one side of the PVC electrical conduit. When you have finished, approximately 1/3 of the conduit should be grooved. This will be the underside of the bar. Drill a hole in one end of the bar to facilitate the intake of the air line. For tanks longer than 90 centimeters, you should have two air lines feeding air into the tank.

    Operation

    • To run your filter, fill the tube with an amount of water that is smaller than the water that will be beneath the conduit in the tanks Place the conduit in the tank and put the air lines in place. Cover with gravel. Fill the tank with water and run the air pumps.