How to Build a CO2 Pressure Regulator for an Aquarium

Pressurized carbon dioxide (CO2) systems often are considered a must for luxurious plant growth in an aquarium. Because of the expense of these systems, many hobbyists build their own CO2 units. The heart of such a unit, the CO2 cylinder, can be purchased easily through welding or beverage outlets. These cylinders are available in sizes that range from 2.5 lbs to 20 lbs. However, a 5-lb bottle will be more than adequate. The 5-lb cylinder will fit into most aquarium cabinets. Using a number of inexpensive aquarium accessories, you can design and construct a CO2 system.

Things You'll Need

  • Carbon dioxide cylinder (10 lbs)
  • Pressure regulator
  • Plastic gravel siphon tube
  • Submersible powerhead (200 GPH)
  • Small packet of filter floss
  • 1/4-inch diameter transparent plastic tube (3 feet)
  • Nontoxic 100-percent silicone sealant
  • Scissors
  • Drill with 1/4-inch bit
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Instructions

    • 1

      Cut the neck of the plastic gravel siphon 1 inch above the large diameter body. Drill a 1/4-inch hole in the large diameter body of the gravel siphon, about 2 inches below the neck.

    • 2

      Fill the first quarter of the large diameter body tube with filter floss (end of the tube on the opposite side to the neck). The floss must be loosely packed. The water should be able to flow through without "blowing" the material out of the tube.

    • 3

      Push one end of the 1/4-inch transparent plastic tube into the 1/4-inch hole in the body of the gravel siphon.

    • 4

      Glue the 1/4-inch transparent plastic tube in place with the silicone sealant. Place the gravel siphon tube aside to dry for at least 24 hours.

    • 5

      Attach (push) the "exhaust" nozzle of the submersible powerhead to the neck of the gravel siphon.

    • 6

      Place the powerhead, with gravel siphon connected, into the aquarium. Use the plastic suction cups attached to the powerhead to hold it in place against the aquarium glass. Position the powerhead. The gravel siphon should point toward the bottom of the aquarium.

    • 7

      Attach the regulator to the carbon dioxide cylinder. Attach the "free" end of the 1/4-inch transparent plastic tube to the regulator nipple.

    • 8

      Plug the powerhead into a wall power source and turn it on. Open the carbon dioxide cylinder tap and watch the CO2 being dispensed through the gravel siphon tube into the aquarium.