How to Plumb More Than One Fish Tank

Plumbing multiple aquariums together through a sump can save you energy and time by using only one return pump. Connecting the water systems of multiple aquariums also increases the total water volume and helps stabilize pH, temperature and salinity. One drawback is that diseases and nuisance algae that infect one aquarium will likely spread to the others. Additionally, if you only use one pump to cycle the water, failure of the pump will affect both aquariums. The trick to connecting the aquariums is to balance the flow of water between them.

Things You'll Need

  • Bulkheads
  • PVC pipe
  • PVC glue
  • Ball valves
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Instructions

    • 1

      Install the bulkheads into the drilled holes of each aquarium, or into the bottom of the overflow boxes. Drilled aquariums with baffles offer the best protection against flooding. Screw the bulkheads until they are tight, but do not use a wrench. The rubber gasket should go on the inside of the aquarium.

    • 2

      Install PVC pipe from the bulkheads into the sump. If you combine the pipes, remember that the pipe continuing from the union should be wider than the incoming pipes to be able to handle the extra water flow.

    • 3

      Set the water flow through the sump and into the chamber with the return pump.

    • 4

      Install lines to each of the aquariums with ball valve on each line on the outlet of the return pump. Use Y-joints rather than T-joints to split the flow of water, as these will create less back pressure on the pump. Back pressure, or the resistance to flow, will stress the pump and shorten its life span.

    • 5

      Open all the ball valves and turn on the pump. Check to make sure water is flowing into the sump from the aquariums.

    • 6

      Adjust the flow to each aquarium by slightly closing the ball valves. Always leave at least one valve completely open to reduce back pressure.

    • 7

      Turn off the power to the pump. This simulates a power outage and will show you if anything floods. Be careful that the return lines to the aquariums do not siphon water back into the sump when the pump shuts off. If this procedure checks out, turn the pump back on to make sure everything starts up again without difficulty.