[Dragon Wrasse]

R/O water is great and is what you want to use for your top off water, I would let the tank cycle without doing water changes. Remember you will need a to start your cycling with a food source for your bacteria, some recomend a piece of raw shrimp.....you will want to keep testing your ammonia and nitrite during your cycle which could take weeks. Your bacteria poplations will peak before your ammonia and nitrite levels begin to drop, when your ammonia and nitrite drop below detectable levels you can start stocking your aquarium.