how to choose the right return pump?

lazycouch · Aug 23, 2020

hey guys. so i’m building my 2nd tank (nano) and i was wondering how i would choose the return pump for this one.. it’s a 20 gallon “frag tank” so instead of being a cube like my other tank it’s rectangular and shorter. does the height and new width affect anything? it’s an all in one tank and i plan on keeping it that way so no sump etc

how many gph should i go for so that it’s working at MAX efficiency?

dimensions 36”x18”x8”

K7BMG · Aug 23, 2020

What is the size of the return pump section?
That will determine more than anything.

I would do a single small gyre for laminar flow.
Have to on back and forth.

lazycouch · Aug 23, 2020

K7BMG said:
What is the size of the return pump section?
That will determine more than anything.

I would do a single small gyre for laminar flow.
Have to on back and forth.

1/2” , just ordered the bulk heads and stuff. what do you mean by have to on back and forth? and what’s the max gph i should go for?

Beluga · Aug 23, 2020

Nice looking frag tank, who makes it?

laverda · Aug 23, 2020

Why did you order bulkheads if your running it as an all in one? 200 GPH max is probably what you would one it really depends on the overflow area.

1ByLand2BySea · Aug 23, 2020

Just as it was mentioned above it all depends what the overflow can handle.

K7BMG · Aug 23, 2020

I was refrencing the physical space of the return chamber that the return pump would fit in.
As you say it is an all in one.
So your return pump will be limited by size.

The gyres can push water and also pull water for back and forth motion.
The gyres would be for tank flow not filtration.

lazycouch · Aug 23, 2020

laverda said:
Why did you order bulkheads if your running it as an all in one? 200 GPH max is probably what you would one it really depends on the overflow area.

they’re for the return pump plumbing it came with nothing as igot it custom made. my friend from the lfs ordered what i needed because they didnt have it. i’m assuming the bulkheads go through the hole where it will connect to the L barb and nozzle if that makes sense because the stock hole is 1 1/4” . thanks for the tips!

lazycouch · Aug 23, 2020

1ByLand2BySea said:
Just as it was mentioned above it all depends what the overflow can handle.

do you mean overflow as in like an overflow box or the built in sump? i don’t have an overflow

1ByLand2BySea · Aug 23, 2020

lazycouch said:
do you mean overflow as in like an overflow box or the built in sump? i don’t have an overflow

I mean the surface area of the part with slits that allow the water to enter the filtration area.

Chibils · Aug 23, 2020

lazycouch said:
do you mean overflow as in like an overflow box or the built in sump? i don’t have an overflow

There are a few limiting factors to consider for your pump.

1. The maximum throughput for your "overflow." The little section with teeth that lets water into the back compartment. For example, say no more than 200gph can pass through. If your pump runs at 300gph, you'll be pushing water out faster than it can come in and the return pump will burn out when the water level drops too low. This shouldn't be an issue in your case, but it's something you have to plan around.

2. The maximum throughput for your return section. If there's nothing but a ½" inlet for your pump to run the return water through, then I believe the max is around 400gph. A 500gph pump running wide open will experience significant head pressure by trying to pump more water than can fit. This is your second obstacle.

3. Finally, consider the amount of return flow you actually want. 5-10x the water volume of your tank is a common flow rate for a sump or filter chamber. In your case that's 100-200gph. Since it's a small tank, you may wish it to do double duty as a flow pump. You could go up to 300 or 400gph if you want, assuming your "overflow" and return line can handle that much water.

Tampaman · Aug 23, 2020

Get a MagDrive 3 or 5 and be happy knowing that it will work forever. Or get a CoralBox/Jebao DC (Something around 1200LPH) pump and you can fine tune flow that way. You can always throttle back an AC pump with a valve if need be.

lazycouch · Aug 23, 2020

Chibils said:
There are a few limiting factors to consider for your pump.

1. The maximum throughput for your "overflow." The little section with teeth that lets water into the back compartment. For example, say no more than 200gph can pass through. If your pump runs at 300gph, you'll be pushing water out faster than it can come in and the return pump will burn out when the water level drops too low. This shouldn't be an issue in your case, but it's something you have to plan around.

2. The maximum throughput for your return section. If there's nothing but a ½" inlet for your pump to run the return water through, then I believe the max is around 400gph. A 500gph pump running wide open will experience significant head pressure by trying to pump more water than can fit. This is your second obstacle.

3. Finally, consider the amount of return flow you actually want. 5-10x the water volume of your tank is a common flow rate for a sump or filter chamber. In your case that's 100-200gph. Since it's a small tank, you may wish it to do double duty as a flow pump. You could go up to 300 or 400gph if you want, assuming your "overflow" and return line can handle that much water.

just the answer i was looking for! appreciate you !

Water Dog · Aug 23, 2020

Grab yourself the small Innovative Marine Mighty Jet desktop DC pump. It maxes out at 326 gph. Runs quietly and you can adjust it down to suit your return flow needs. I’ve used several for a number of years to reliably to run reactors and my ATS. These are meant to run on Innovative Marine’s line of AIO tanks and would suit your needs quite well. Just make sure the 4.13" x 2.5" x 3.4" dimensions will work for your return section size.