I agree with Newman on the timeframe to get things stable for a marine setup like yours. It is a slower maturing process than freshwater. Both setups can be started/seeded rather easily, but a marine tank takes longer to level out, and different types of algae are inevitable in the course of time until things are mature. The 'algae-scrubbers' you see being built kinda solve this for you, but only by growing the algae in a small controlled area instead of your display tank.