[jbaker]

The more connections you have between the tanks the more possibilities there are for water leaks. I'd use one tank for the whole thing. I've got a 55 gallon divided into 3 sections: sump, fuge, and return. The return line to the tank is split so it can flow back to the sump (where my skimmer is located) and this water flows very slowly into the fuge, and then into the return section. The drain lines from my tank go directly into the return portion of the sump/fuge tank. All the water flow is controlled by in line ball valves. I've also used 100% clay inscented kitty litter for the fuge.