How to Build a Closed-loop System for an Aquarium

Building the Closed Loop

• 1

  Choose the pump you would like to use for the closed loop. The pump will determine your flow rate and the PVC size you will need. Choose something reasonable for your system. If you have corals, higher flows will be required for coral growth. If you have only fish, you can use a smaller pump.

• 2

  Draw out what you want the closed loop to look like. Measure the lengths of pipe carefully. Remember that the pipe will sit inside the bends, so add about 1/2 inch to your measurement for each attachment at the end of the pipe. When drawing your design, plan on adding several unions so you can disassemble the pipe without lifting the entire system out of the aquarium.

• 3

  Cut the pipe to the measured lengths. Generally, it is easiest to cut and fit as you go so you can make adjustments to the pipe length, if needed. Start at the pump and work your way into the aquarium. Do not glue the pipes yet, just dry fit them together.

• 4

  Glue the PVC pipe together in the same way you dry fitted them, starting from the pump. To glue the PVC, you must first prime the pipe with the purple primer, then add the glue. Twist slightly to be sure the glue is spread evenly in the pipe. Hold in place for a few minutes to let the glue set.

• 5

  Let the glue cure for at least 24 hours before putting any of the pipe in the aquarium water. Place the glued pipe in a well ventilated room to let it dry.

• 6

  Add the pipe into the aquarium and apply your inlet screen on the part where the pump will pull in water. This is to protect the animals in the tank from being sucked into the loop.

• 7

  Turn on the pump. It may sputter as it pulls in the excess air, but once the air is out of the line, it should pull water through the inlet and push it through the loop. Your animals will thank you!