DIY Oscillating Return Device

Attach one powerhead to the far right side of the aquarium and in the rear corner. Place the second one on the back rim of the tank and directly in the center. The idea is to find the best place to attach the powerheads so that they work in tandem to achieve maximum water circulation. Dead spots are areas within the aquarium where there is no water movement and you do not want any dead spots.

The gallons per hour production of the powerheads will depend on the size of your tank and the type of water movement you wish to achieve. The Hagen 402 powerhead moves 270 gallons per hour. which is ample for most home marine aquariums of 30 to 75 gallons.

There are three types of water movement; laminar, surge and turbulence. Turbulence is the random flow of water in multiple directions, and except for rare cases where unusual fish and corals are kept, the most desirable type of duplicated water flow movement is turbulence.

Take one of the 1-inch PVC pieces and glue it into one end of the 90-degree elbow. Glue the 45-degree elbow to the other end of the 1-inch PVC pipe piece. Glue the second 1-inch piece of PVC pipe into the open end of the 45-degree elbow. Attach the PVC 90-degree elbow over the Hagen output nozzle. This connection should fit smoothly and tight and should not require any modification. Be certain to allow the entire assembly to dry completely before placing on one of the powerhead output nozzles. Many experts recommend a full 24 hours.

Direct the flow of the powerhead that is mounted in the rear corner of the tank so that the built-in 45-degree plastic cylindrical nozzle opening points to the front of the tank. You are actually trying to direct the water flow to an area that would be considered the exact center of the tank in depth, length and width.

When placing the 90-degree assembly to the central rear powerhead, it should slip-fit onto the powerhead's outlet nozzle and remain tight, but with a little play. Direct this water flow straight ahead and pointing down 45 degrees. Plug in the two powerhead pumps and the water flow will begin to replicate the ocean's natural currents. The placement of these two powerheads should cover every area of your tank but some slight adjustment may be necessary. A good way to check for dead spots is to drop a small piece of cloth ribbon into the tank, the ribbon should never find a resting place.