same thing as a FW, you have to wair until nitrates hit 0 and you are sure the tank is stable. the general plan i use for stocking a reef tank is: live rock, nitrates 0 + 2 weeks, cleanup crew, nitrates 0 + 2 weeks, 1st fish, nitrates 0 + 1 month, corals and additional fish (at a rate of 1 per month). the idea is to make sure the system really is stable before you bring in any coral...its a slow process