DC Return Pump Flow by Percentage

[BradVol]

I can find lots of info on calculating return pump flow for a given output flow rate, but I can't find anything about how that varies with percentage on a DC pump.

If the pump is at 50% does it produce 50% of the flow rate? Or is the flow rate not linear?

I'm running a Jebao DCP-5000 in a Red Sea Reefer 170. Head height is 4 ft and by the time I account for 2 elbow joints, pipe diameter, and a reactor I'm using 6 ft as the calculated equivalent height. At 6ft and 100% the pump provides 530 gallons/hr. I've been running the pump around 70% but I have no idea if that's too much, too little, or about right.

 

[Wildreefs]

I don’t believe it is linear, mine shuts off right around 20 percent but runs well at 30 percent. I think DC pumps fall short as a whole in terms of torque and movement . Will be going back to AC when this one burns out

 

[mfinn]

I can find lots of info on calculating return pump flow for a given output flow rate, but I can't find anything about how that varies with percentage on a DC pump.

If the pump is at 50% does it produce 50% of the flow rate? Or is the flow rate not linear?

I'm running a Jebao DCP-5000 in a Red Sea Reefer 170. Head height is 4 ft and by the time I account for 2 elbow joints, pipe diameter, and a reactor I'm using 6 ft as the calculated equivalent height. At 6ft and 100% the pump provides 530 gallons/hr. I've been running the pump around 70% but I have no idea if that's too much, too little, or about right.

After doing a google search it said a Red Sea Reefer 170 is 34 gallons.
So using that as a reference point I usually want to shoot for 4x to 5x the tank volume through the sump.
So right now if your calculations are right you are pushing 370+ gallons per hour at 70%.
If this were my tank and pump I would probably want to cut it back to 35%-40% tops.
Unless you have a apex setup with a flow meter ( not sure if there is any other kind) we are just guessing at the real flow rates. I suppose you could setup up your pump in a large tub with the exact same plumbing you would use on your tank and actually measure the flow. ( how much water flows in say a minute or 2).
But I just make a guess using the flow charts most pump manufactures publish.
Then make adjustments based on noise the overflow makes and the drain makes.
Do whatever adjustments on the plumbing that I can to help with noise levels.