If you have a sump, just install a skimmer there. The HOB skimmers that I'm familiar with all use pumps that hang in the tank a few inches below the surface. So unless you spend another $20-$30 on their pre-skimmer boxes, the surface junk is better collected through the overflow leading to your sump.
Plus, in-sump skimmers are stronger and more efficient in my opinion. Especially the Euro Reef skimmers (wink, wink).