Leaving the lights on for a short time (4hrs a day) will allow some algae to grow and uptake any nutrients which, IMO, establishes an important part of the life cycle in a reef tank. You'll need to add a CUC to eat that algae, but you'll need to do that eventually anyway. Encouraging that initial growth of algae as the tank is cycling also provides a food source for various pods which will then also establishe another level of the food chain / life cycle (little herbivorous pods eat algea then the larger pods will feed off the smaller pods - so on and so fourth).
By cycling a tank without the lights on, for at least a short time throughout the day, is leaving out an important means of filtration as well as missing the opportunity for the early establishment of diverse animal life.
Jeremy
