View Full Version : one or two return pumps?

joy solomon
01/13/2008, 11:27 AM
Hi Marc,

I really liked your sumps 101 article. It was extremely helpful.

I am getting ready to set up a new reef aquarium. It is 7' x 2' x 2' with 2 corner overflows and two returns. My sump is 48" x 18" x 17" with a bubble tower and 3 chambers (skimmer, refugium and return). I am planning to use a submersible pump as a return. Do you recommend using one return pump to feed both returns or two smaller pumps each feeding its own return? Either way I'm planning to have both overflows flow into the same bubble tower.

I would greatly appreciate hearing your opinion on this.


01/13/2008, 12:14 PM
Do you know what size drains your display tank will have?

Do you want a submersible or an external return pump?

joy solomon
01/13/2008, 09:14 PM
The drains are 1.5". I'd like to use a submersible pump (or two). I am planning on using 2 Tunze streams in the display for most of the water movement. Also, my skimmer will be in the sump and is a down-draft running off a 800GPH pump.

Thanks for your help!


01/13/2008, 10:24 PM
With those drains, you don't have to worry about the return pump size too much. Your tank measures out to be 210g. However, your sump is 48" long, which when divided into compartments reduces the time allowed for microbubbles to rise and pop.

All you need is a single return pump. What I would recommend is that you use SpaFlex tubing from the pump, and run that flexible tubing up to a Tee fitting that is dead center under the tank. From the Tee, run the plumbing both ways to the return bulkheads. That way your return pump will push an equal amount of flow into each return.

Each drain can handle up to 1500gph, but it doesn't have to be nearly that fast. Based on your sump size, I would use a Mag 12 or Mag 18, using 1.5" plumbing all the way until you reach the 1" bulkheads.

The Mag 12 and Mag 18 pumps have 3/4" threads on the outlet. By doubling the plumbing size on that pump, you'll get the promised flow out of them. Either pump will do the job. You'll need a 3/4" to 1.5" bushing, then a 1.5" slip/slip union, then 1.5" SpaFlex tubing, 1.5" Tee, 1.5" rigid PVC, 1.5" elbows, then a bushing that is 1.5" to 1", then 1" PVC to the bulkhead.

The SpaFlex prevents vibration from the pump to resonate in the plumbing.

The union allows you to disconnect the pump easily.

And I would recommend that the bulkheads you use be threaded / slip. I'm talking about the inside of the bulkhead only. The flange end, the part that is on the inside of the tank with the rubber flat washer, that section should be threaded. The other end, internally should be slip. The outside of the bulkhead will have threads, but these are only there for the nut to screw on tight, and does not match any threaded plumbing fittings.

joy solomon
01/14/2008, 02:34 PM

Thank you very much! I'm going to visit the hardware store today with my list!