DIY Closed-Loop Maxi Jet

The Maxi-Jet 1200 is an aquarium pump and powerhead unit used to power under-gravel filter systems. The Maxi-Jet features a venturi aeration device, a silencer and an adjustable air filter that permits the user to fine-tune air volume and water mixing as desired. A closed-loop Maxi-Jet system is when two Maxi-Jets are connected in tandem to provide maximum aeration. Closed-loop systems are used for larger aquariums over 20 gallons. Such systems add current and flow to the system -- allowing water to move through the filter at the proper flow rate, while increasing tank flow.

Things You'll Need

  • 2 Maxi-Jet 1200s
  • Plastic pump holder
  • 2 PVC U-joints
  • PVC glue
  • Backup filter-pump system
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Instructions

    • 1

      Slide the impeller for each powerhead into the impeller wells, and then snap on the impeller covers. The impeller is a long, pencil-shaped piece with a small fan -- the actual impeller -- mounted on the end of it. It slides into the powerhead (or base) of the Maxi-Jet. The impeller cover simply snaps on, over the impeller and attaches to to the powerhead.

    • 2

      Attach the under-gravel adapter, a long tube-like piece, to the intake. The intake is a small plastic shaft that protrudes up from the impeller cover on the powerhead. Slide the adapter onto the intake by hand. Repeat this procedure to assemble the second Maxi-Jet 1200.

    • 3

      Swab PVC glue onto the inside of the PVC U-joint. Slide the glued end of the U-joint over the free end of the adapter, which was just attached to the powerhead intake. Glue the plastic strainers to the bottom of the U-joints. The strainer is a plastic tube-like piece with vertical slots.

    • 4

      Allow at least 24 hours for the PVC glue to set and dry before placing the system into the aquarium water. Use an old, spare backup filter overnight while the new loop system filter dries.

    • 5

      Connect the spare filter to the tank. Connection of the spare filter may vary some, depending on the type of filter being installed. However, most secondary filters simply hang over the side of the aquarium, with the filter tubing inserted into the water. Hang the back-up filter in this manner, and plug it into an electric wall socket.

    • 6

      Place the two Maxi-Jet 1200s side-by-side in the plastic pump holder. The plastic pump holder is a clear plastic tray that has a lipped back that hangs over the edge of the aquarium back. Hang the pump holder over the back edge of the aquarium, after the Maxi-Jets are in place.

    • 7

      Plug the Maxi-Jet powerheads in, and allow the closed-loop system to work.