You can use any aquarium, and alot of people just have tupperware type tubs. It can be as simple or as complicated as you want. I use a 29 gallon high aquarium, had some glass peices cut for a couple of baffles that I set into the tank with silicone.
It allows you to drain into the sump (thru a filter sock if you want, to filter some of the bigger stuff out of the water.) You can sit an in sump skimmer right in the water. If you don't have a reef ready tank, you'll need to use an overflow box to drain the water to your sump. Lots of people here use them and could give you some info on it. You may be able to do a search on sumps and see if you find anything helpful.
It is worth checking into.
