I use to have fish tanks(9) and my buddies had a combined total of 28 fresh and saltwater. If you start a saltwater, get some water conditioner and live rock. For saltwater, its all about the liverock. Get a 40 gallon wide(more surface area for better oygen exchange) and keep it barebotttom and stock it with live rock. Throw in some table salt every so often and buy some decent quality salt mixture. Also build a wet/dry/bioball filter for cheap, and you can pretty much put whatever you want in there and it will thrive.
When I'm older and have some money, I'm going to build a few 200 gallon tanks and stock them with cichlids and saltwater arrangements.
