take what you will from this: fact, the 2 above posts state that they have lower lighting, comparatively, ie t-12's and PC's; coralline likes lower light situations
if you want coralline to grow, you simply have to have some to begin with, and wait, patience and stability are the keys
if you have coralline and do not want it, sorry, you are out of luck, you can scrape it off your tanks sides, front and back, but not off the rocks