Although I would never consider buying one as IMO they are too delicate, one appeared on a rock and has subsequently started on another.
It has been growing on the underside and side of a rock near the bottom of the tank near a window. Therefor I think it needs bright light but not the intense light produced by Metal Halides (MH).
I ensure that it is getting an indirect current and focus on getting phyto to it.
You cannot take them out of the water and I blast any crud that eventually will stick to it. So, don't aggitate the sand near it.