Live Rock needs no light in particular, however some of the critters that may come on it can use some light. I kept my live rock, in a tank, without lights for over a week before my system finally came in and I had no problems what so ever. The important things are to have saltwater, obviously, (to the right salinity), heat the water to appropriate temp, and offer some flow to help keep the water moving and I believe some algea cannot grow well in moving water.