And a 100g is only $75

http://www.tractorsupply.com/webapp/...&Special=false

I'd opt for the 100g only for the fact you can store your rock and corals easier. The 50g is pretty shallow and you will have a hard time keeping most of your rock submerged. The 100g is a lot taller and you can always keep the rock on the bottom, then throw eggcrate ontop for your corals. And of course, you do not have to fill it all the way up!