600+ gallons. I already have a 300, so if I am going to upgrade, it has to be noticeable. I am trying to avoid the price shock of a brand new tank, but I am looking at a 1200g for 11grand right now, but if I can get into a used tank in the 600+ (there is no tank too big for me, if it is moveable, I am interested) it would be nice as I am always into saving some money. Thanks