Alright Here is a pic of what I did and i think it is really affective.
First off i have my sump split into three sections. Left side is where the protein skimmer is, center is my return pump, and the right side is my refugium. Water is split using a T between the right and lift side. I then have a mj that pumps water from the refugium to my frag tank. You can see the pvc tubing used in the front right of the tank. I use a u-tube to bring the water back from the frag tank to the refugium. In the rufugium i use a pvc with cap that acts as the prefilter. This also keeps the water at a constant level. I hope this makes sense.
The back left of the frag tank you can see the 2 inch pvc.
I hope this helps a little. I considered directing the water from the display to go into the frag tank instead of the fuge side of the sump but if i did this i would have a lot of air bubbles in the frag tank and decided to use the pump instead.