How to Build a Protein Skimmer

A protein skimmer is a piece of equipment on a saltwater aquarium used to skim proteins out of the water. The proteins are organic waste products from the living creatures in the tank. Removing the waste with a protein skimmer before it can break down into toxic chemicals will protect the health of your mechanical system as well as the inhabitants of the tank. Tank water is pumped into a cylinder or column and churned with bubbles to make foam. Organic waste is carried by the bubbles to the top where the resultant scum is skimmed off into a collection jar. The protein scum resembles sea foam you would find on the beach, created with the very same process by nature. You will need a larger skimmer for a larger tank, as more waste is produced in a larger aquarium. Commercial skimmers feature reaction chambers no smaller than 6 x 4 inches wide for a 20 gallon tank and up to 24 x 6 inches in diameter for tanks over 100 gallons (see Resources).

Things You'll Need

  • Reaction chamber (Acrylic or non-toxic plastic. Rectangular will work but cylindrical is best)
  • Chamber for bubble column (cylindrical or cone-shaped works best; glass, plastic or acrylic, open on at least one end)
  • Cup or jar for collecting skimmed protein
  • Airstone and pump
  • Flexible tubing
  • Non-toxic, water resistant adhesive
  • Drill with plastic/acrylic friendly bits
  • PVC pipe elbow joints
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Instructions

  1. Passive System Protein Skimmer (For Small Tanks)

    • 1

      Create two holes at the base of your reaction chamber, which will sit in-tank. Water will enter and exit passively from the bottom of the skimmer.

    • 2

      Attach hooks to the top edge of the reaction chamber on one side using non-toxic, water resistant adhesive. This will hold the protein skimmer to the side of the aquarium inside, at or below the water level.

    • 3

      Insert an air stone hooked to an air pump with flexible vinyl tubing into the bottom of the reaction chamber. This will agitate the water and create the bubble column. You will need to check the pump and air stone frequently for wear and mineral build-up.

    • 4

      Top the reaction chamber with an open end of the bubble column chamber. This is where the foamed proteins will exit the reaction chamber. Seal off any other exit the foam can make at the top of the reaction chamber. You want the foam to build up in the bubble column chamber.

    • 5

      Install the collection cup at the top of the bubble-foam cylinder. This can be a cup that sits over the top of the cylinder with "drop" space to the floor of the cup (make sure the bottom is sealed around the central cylinder), or can be a hose leading off to the one side at the top of an enclosed cylinder. The collection cup should be the only place the skimmed foam can go. Old foam will be pushed aside by the action of new foam bubbling upward.

    Active System Protein Skimmer

    • 6

      Drill an inlet in your reaction chamber for water passage. The inlet should be near the top of the reaction chamber. This is where water will enter the protein skimmer from the tank.

    • 7

      Install an elbow joint to position the water input at an angle downward to the inside wall of the chamber. This will increase turbulence within the chamber, essential to making bubbles. A cylinder-shape will help create a cyclone-effect in this chamber. You may choose to install a venturis valve to further agitate incoming water when you plumb the protein skimmer to the aquarium. Seal the entry hole water tight around the joint.

    • 8

      Drill an outlet in your reaction chamber for a return pipe. Water should exit the reaction chamber to return to the tank or to the sump from the bottom of the reaction chamber, where turbulence is lowest.

    • 9

      Install an elbow joint inside the reaction chamber to angle the entrance of return water as close to the base of the reaction chamber as possible. Angling the return pipe entrance downward will minimize bubbles returning to the tank. Again, seal the entry hole water-tight around the joint.

    • 10

      Place your bubble column cylinder on top of the reaction chamber. This is where the bubble foam will form and exit the reaction chamber. Just as with the passive skimmer in Section 1, Step 3, seal all other exits the foam could make.

    • 11

      Install a collection cup for the foam. This is the skimming portion of the protein skimmer. See Section 1, Step 4.

    • 12

      Plumbing water through a pump before it enters your protein skimmer will increase turbulence within the protein skimmer. Adding a t-joint with an air valve where the pumped water enters the reaction chamber will allow you to adjust the size of the air bubbles.