I have a Richard Rendos model. I had an "aquatecture". Tom Kloth in Atlanta, GA built the Aquatecture model. I decided I needed a larger model so I sold his and built my own dual chamber. I am working on a new design now that has a spray bar inside. I would say the Geo and the My Reef Creations are good models. If you are near Atlanta, you can get one from Aquatecture. Tom makes quality stuff..including protein skimmers, sumps, wet/dry's, and calcium reactors...oh, yeah, and acrylic tanks too.
Here is one I built for a friend a while back...4" diameter acrylic 24" tall...run by a Mag 2.