i too noticed this. In my works reef, the stuff grew crazy good under 20k halides. My "ex" boss decided to replace them with AI hydras. As soon as he put those leds over the tank, the coralline pretty much stopped. It only grows under shade. Now that i got his position, i keep thinking about getting t5's. I hate these lights.I always like it when it would get thick and start plating. Made some interesting formations, plus helping keep hair algae down.
Not seeing that so much anymore with leds. In my tanks it was more a mh thing.