Determining Return Pump Flow Rate

[PeterC99]

I'm running a Vectra m2 DC return pump rated at 2000 gph. If I run the pump at 50%, can I assume that my flow is around 1000 gph?

Thank you.

 

[Bryknicks]

If you are not running a manifold and return goes straight from the pump to the tank then you would just need to factor in head loss. So it will be less than 1000gph but not too much if you have a short run.

 

[PeterC99]

Not running a manifold but does go through my UV light before going to tank.

Return Pump through UV light and then to tank. Total distance about 4 feet. Any rules of thumb to estimate head loss?

 

[Bryknicks]

According to their chart for head loss you should be getting around 850 gph at 50%

 

[PeterC99]

Going to lookup the Chart. Thank you!

 

[Snoopy 67]

Now you have to consider the "recommended flow" for the uv.

 

[PeterC99]

Oversized the UV - 57 Watt for 90 gallon tank.

 

[reddogf5]

The head loss chart I saw didn't include anything other than full speed, I would contact their tech support and find out what "50%" means. It could be calibrated to give half the flow output, or it could run the motor at half speed, which would be nowhere near half the flow rate.