Vivid Aquariums recommends using two return pumps instead of one large return pump. We have known too many hobbyists who returned from vacation to find they had lost everything in their aquarium all because the single pump that ran their system had failed. Using two return pumps greatly reduces the chance of your system completely shutting down, and gives you peace of mind. If one pump fails the second pump will keep everything alive until you have time to fix or replace the broken pump. Remember even the best pumps fail eventually.

The return pumps should combine to turn over the volume of the aquarium 10-15 times per hour. Ex. a 100 gallon aquarium should have between 1000 and 1500 gallons pumped through it every hour depending on the type of livestock being kept.

Any powerheads placed in the aquarium for flow should combine to cycle the volume of the aquarium 6-10 times per hour. The stronger return pumps you have the less need you will have for powerheads in your aquarium.

The “head” is the height that a pump will pump the water. Make sure to measure how high the pump will have to pump the water. If you have more than two elbows in your return line you may need a slightly stronger pump since elbows reduce the flow. Finally, make sure to account for any other accessories that the pump must pass the water through, such as chillers, canister filters, U.V. sterilizers, etc. It is better to get a stronger pump and turn it down a little than one that is not strong enough.