With out lights you will have unnecessary coraline death. This would be seen as the Coraline on the live rock turning white. I find diatom algae easy to deal with, and prefer to keep my live rock as live as possible to include what life forms came with and on the live rock besides just keeping the bacteria alive. The best way to do this is run the lights, all circulation pumps and a skimmer if you have one. Feed the tank a little fish food when first starting your tank cycle if the water tests do not show an ammonia presence (usually this is not necessary as there is usually some die off associated with new live rock). Make sure you have a new, good ammonia test kit. Test the tank at least twice a day (morning and evening). As soon as the level gets above one part per million, change enough water to bring it down to safe levels. For example, if your test shows that you're at 1.25ppm, you'll need do approximately a 25% water change to get it below 1ppm. It may take 4 to 7 days or more of water changes until the tank cycles. Start testing for nitrites. When the nitrite readings drop to zero. Do a large enough water change to bring your nitrate readings below 20 ppm. Slowly add a few fish at a time after the last water change that reduced you nitrates to below 20.