Honestly, if it is within your means to add a sump, do so. In sump skimmers are so much more efficient that it isn't even funny. I've heard the CSS 220 is decent, but I had a CSS 60 before my remora and it kept overflowing the cup with clear skimmate. For whatever reason it would just freak out randomly and overflow onto my carpet. Coralife could not figure out what the problem was so I got my money back. I have heard great things about the Octopus in sump skimmers, and they make a HOB that is rated pretty high but I don't know if anyone has had any experience with that one. There is a huge thread in the lighting and filtration forum on octopus skimmers. Oh, and compared to other comparable skimmers, they are dirt cheap.