I have read that there are beaches made up of this stuff. When it dies it pretty much turns to sand. I had it in my tank pretty much the whole time, since I ran a Ca reactor and Kalk reactor calcium wasn't a problem. Its also supposed to use up nitrates just like most other algaes. Mine went A sexual (or is it sexual, I can never remember this stuff) a few times. When it does the tank clouded up big time. The stuff just died off, turned white then into sand. Other then a cloudy tank it never bothered the corals or fish.