But if u r to buy from a reefer, then no need to wait lah... straight away can add into ur tank... but u must take the rock from his water-filled tank and rush home quickly.
You need to make ur rockscape as high as possible to hide the pumps behind. You can also push the scaping nearer to the back so u can have another small island in front. No need to leave too much room behind, wasted space.