Vectra M2 correct setting? Watts to GPH?

legacy2mj · Jan 20, 2024

I have looked and tried to find a simple, realitivly accurate gauge of numbers to help get my return amounts figured out easier. The adjustments on mobius show % from 0-100… and then current wattage being used. I don’t need it to be exact. Just a decent ballpark. I know the max flow is 2000 GPH.
I have a 120 display, typically ~5’ of 3/4 plumbing.
If I knew my good “ballpark” recommended turnover rate was accomplished in the X1-X2 % range… that would be ideal.

DCR · Jan 21, 2024

It is impossible to do because the resistance of the external return piping has such a major impact on the pump performance. With 5 ft of 3/4" return piping, you are probably getting anywhere from 200-350 gph. This is just based on my experience with sizing piping for fluid flow as an engineer. Beyond that the head losses are going to increase exponentially more than the pump capability.

The best way to develop a correlation would be to stop your return pump and siphon several inches of display water down into your sump so that the sump is almost full. Then start the pump and measure the time it takes to drop the sump level a certain number of inches. The amount of water transferred in gallons is the sump length (in inches) times width (also in inches) times level drop in inches divided by 231 (cubic inches to gallons). Divide that by the time in seconds that the pump was running and multiply by 3600 (secs per hour) to get gph. You have to make adjustments if the sump has multiple levels develop within it due to baffles during the pump down to calculate the volume pumped from each chamber. You can repeat the test at various pump speeds. Alternatively you can install a flow meter. I personally would not worry about it. The exact return flow is not that important. Just enjoy your tank.