That prococess is also called "cooking" your live rock. I've had the best results when theres no light at all, die off of unwanted algae (coraline will grow back don't worry). Also, if you set up about 3, 5gallon buckets of NSW and you take a rock... dunk it in the first bucket for a while then move on to the secnond and then onto the third you will see the buckets getting clearer and clearer... that means less stuff is comming off the rocks. Do that with each of your rocks every few days (while curing the rock) and you'll have the nicest rocks in town!