Gravity driven scimmer and sump

[DanNolan]

Can I use gravity to drive my water flow through my scimmer and into my sump/refuge, using a pump to return the final product back to my main tank?

Below is a diagram



1. Overflow from main tank
2. scimmer
3. bubble trap/sump
4. refuge
5. return
6. return pump

Is it possible to use gravity to drive the flow through the scimmer and into the refuge if the height of the scimmers output is below the input into the tank but above the the main tank overflow? I am currently not sure it would work, would I need to raise the scimmers output to higher than the sump? Or would the flow continue as long as the input and water line inside the scimmer are above the waterline inside the sump?