a sump with a fuge is the way to go, I have about a 4" sand bed it the fuge and some cheato, makes a big difference in the water quality, the cheato absorbes nitrate and the sand bed helps the filtering system, I set one up for a friend about a year ago because he never could keep corals in his tank and since then his tank has done great. I would not have a system without it. For your pump lets say you are flowing in 600 GPH and your return for the pump is going up 4 ft. you would just need to find a pump that will pump 600 gph back up to the display tank with four feet on head, when looking at a pump it will give you the gph and head loss to help figure out what you need, another advantage to the sump is that is were your water evaporation showns so you can top-off at your sump and keep the DT at the same water level, the sump helps keep your water level consistant thus your SG is more stable. Hope this helps
