DIY Aquarium Skimmers

Aquarium protein skimmers are filters that remove organic compounds from saltwater before they have a chance to break down and turn into nitrates. The skimmer works by mixing saltwater with air bubbles to create a foam. A cup at the top collects the foam, which is then removed and discarded. Skimmers can cost in the hundreds of dollars, but it is possible to make your own.

Things You'll Need

  • Large diameter plastic tube
  • Plastic tubing
  • Powerhead or pump
  • Aquarium-safe glue
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Instructions

    • 1

      Design the reaction chamber. The reaction chamber is the main tube where the air will be mixed with water. The height and width can vary, but the taller it is the more time the bubbles will have to react with the water, leading to better filtration. Wider tubes will require greater pumps and more bubbles to work properly, but can filter better as well. You can make this chamber out of any aquarium-safe watertight material, such as PVC, plastic or glass. You will need to seal the bottom, so choose something you can work with.

    • 2

      Adhere a cap on the bottom of the reaction tube. You can use glues so long as you coat the inside seem of the tube with aquarium safe silicone. PVC glue is safe for saltwater aquarium systems when it is fully cured.

    • 3

      Drill a hole near the bottom of the reaction chamber and insert a tube. The tube can be flexible clear tubing or PVC. One end goes into the reaction chamber, the other will be connected to a water pump, so choose a tube that will fit with your pump.

    • 4

      Drill a hole near the top of the reaction chamber. This is where the water will exit. Do not drill the hole at the top of the chamber, as this will drain the foam as well. Aim for about a quarter of the way down from the top.

    • 5

      Attach a reducer to the top of the reaction chamber. The reducer will concentrate the foam and raise it into the collection cup. The reducer simply narrows the diameter of the reaction chamber. These are available for PVC pipe at hardware stores. Don't make the reducer too small or the foam will not be able to rise in it. An internal diameter of at least a half inch is a good start. The bottom of the tube should sit at the top of the reaction chamber inside the reducer. The tube should be about 4 inches in length.

    • 6

      Attach the collection cup. The tube will go inside the collection cup and stand about an inch from the bottom of the cup. The purpose of the cup is to collect the foam and you will need to remove it periodically to empty the leftover foam (called skimmate). The cup itself can be made of anything; even a plastic kitchen food storage cup with a hole cut in the bottom.

    • 7

      Attach the water pump and turn on the skimmer. If water floods into the collection cup, there is too much flow into the skimmer. Choose a smaller pump or reduce the amount of water the pump is able to intake (although restraining the water will reduce the life of the pump). If the water does not reach the outlet, the pump is not big enough. You can get a bigger pump or add another one. Alternatively, you can raise or lower the height of the reaction chamber or the tube connecting the chamber to the collection cup.

    • 8

      Adjust the length of the tube between the reaction chamber and the collection cup to collect the type of skimmate you want. Some people prefer to "skim wet," meaning there is a bit of water mixed in with the skimmate in the cup, while others "skim dry" where the skimmate is mostly dried organic matter. The choice is up to you and you can skim wetter by reducing the length of the tube or skim drier by making it longer.