Retirn pump size

[PAdrone]

How do I determine what size of return pump that I need? It will be on a 120 gal plus sump. Sump will be on the same floor as the main tank, possibly on the other side of the wall.

 

[mike550]

@PAdrone my sense is that the entire volume of your tank should turnover at least four times an hour, but I think most people strive for more. So let’s say you want to turnover your 120G six times an hour. That’s 720 gph — keep in mind that’s a minimum target. The second pest of your Q makes this messy because flow rate is affected by head pressure from plumbing, height differences etc.

I have a 120G and am using a Vectra M2 which is rated for 2000GPH. Obviously that’s not what I can do in my tank, but the pump gives me sufficient power and flow.

 

[Kfactor]

just get a dc pump bigger and tune it for what you want

 

[sc50964]

just get a dc pump bigger and tune it for what you want

10x turn over ratio but def agree with the above pt.

 

[Tcook]

I use 2 x Cor20 pumps on my 120. One also supplies the chiller an UV. Will you run manifolds? How many 90 degree bends in your plumbing? What size pipe for returns. I like to use 2 pumps incase one goes out.

 

[Pistondog]

How do I determine what size of return pump that I need? It will be on a 120 gal plus sump. Sump will be on the same floor as the main tank, possibly on the other side of the wall.

4 or 5 times total volume.
Hard to determine actual pump rate unless you have an inline flowmeter or measure it at the tank inlet by filling a known volume in x seconds.
The dc adjustable option allows tuning in drain systems.

 

[All_talk]

10x turnover is a bit of a holdout from the old days when we used return flow as part of the water movement in the tank. With the wave/flow pumps we have now, the rate through the sump can be reduced a bit. Target flow rate will depend somewhat on the filtration you are using but somewhere around 5-6x would be a good place to start.

As others has said, the pump will need to be oversized to overcome head pressure from height and restriction in the plumbing.

I also agree that two smaller pumps is better that one, redundancy should be standard in life support systems.

DC pumps are great and provide easier adjustability and control options. But if budget is an issue, AC pumps work just fine too.

If you want a safe simplified formula I would add the tank and sump volumes, multiply that by 10, and pick a pump (or pair) that are rated for that at zero head pressure. Again as others have said, you can always throttle back.

 

[ScubaFish802]

Here's a more comprehensive read https://www.bulkreefsupply.com/content/post/md-2020-11-how-to-size-a-return-pump

 

[PAdrone]

Thank you everyone for the excellent information!

 

[Kfactor]

on my new build am only doing 3 to 4x turn over with lots of flow in the main tank with power heads

 

[DCR]

Assuming you are comfortable using about 3-5X turnover as many recommend, use 1" return pipe and look for a pump that can deliver at least 600 gph at 6-8 ft of head. Look at the pump curves not the rated capacity which is at zero head. The actual flow will generally be about 50% of less of the so called rated.

 

[erm0715]

I'm setting up a 120 but went with a Jebao DCP 8000. I have a DCP 3000 on my Prostar60 since August and it's dead silent and also as mentioned before as a DC pump I can tune it up or down.

I'm not certain the accuracy of the flow charts online but at 6ft of head it's around 1000 gph maxed out so I intend to tune it down and aim for 4-6x. I was going to go with a DCP-10000 but they were out of stock and as they are DC pumps both would be in range.