I def respect haya's opinion but i didnt like the control on the half cut pipe, so i built in a gate valve for more control on the return to the sump...in the end its all up to you, but def get a specific pump to feed the skimmer
Sorry for the slow reply. The best way was to take a picture but I needed batteries for my camera. I wanted to run the skimmer first with the dirtyest water. I did not use an additional pump. I am happy with this setup.
I had to drill a hole in the side of my sump because of height issues. Let me know if you have any questions. Once I figured out how how to connect the plumbing, it was pretty easy. The documentation provided with the skimmer isn't very good though.