Forget the idea about the air stone...the ocean doesn't have pockets of bubbles coming out of the sand....Throw a powerhead on each end of the tank, and make sure there are very few dead spots of current...
If you are going FOWLR, make sure you get fish that don't bother corals or eat inverts if you plan on changing it to a reef in the future. As you will likely not see your shrimp any more if so.
When adding coral its a whole new ballgame like he said... FOWLR tanks only require you to test salinity, ph, and nitrates....
Reef tanks essentially you need calcium, magnesium, alkalinity, nitrates, ph, salinity, and nitrites all checked on a regular basis...not to mention that corals need to be fed regularly as well, and also need a higher degree of light to produce zooanthellae.