When I had my 46 gal
reef running I had what I believed to be a moderate cyano
problem. Tried everything recommended except food reduction without luck. The solution seemed to be to just suck the stuff off the substrate, weekly, when I did my water changes.
A few months ago I moved up to a 72gal tank and haven't had problems until 2 weeks ago. My new tank has a 33gal sum with large fuge loaded with Green Grape Carlupa & a few inverts. Some ruby/maroon colored substance started growing on my LR
and Metalic Star coral. I could not remove very much with a toothbrush. Now I have ruby colored sheet-like material growing between the polyps of my Sun Coral. It was easy to remove with a brush but came back in a few days.
Additionally, I have a dark green growth spreading out over my substrate (sand). It can be sucked off the surface but starts to return within a day. It looks terrible.