The amount of time the rock takes to cure is related to a number of factors: how long the rock has been out of the water, how close the chemical make-up of the water you use is to the water that the organisms on the rock were growing in and how well you care for the rock while it is curing. Don't add any invertebrates until after the ammonia spike, nitrite spike and nitrate spike have passed. You should provide circulation, aeration and a heater for the live rock, whether you cure it in the tank or in a tub, otherwise the water will putrify and a lot of organisms will die that might otherwise make it through the curing process.
