...if this is actually an algae. It's very light tan/brown in color, almost transparent. No green or red color to it. It's filamentous or hairlike, short, but it also has a clear "slime" layer covering it. The slime layer brushes off easily. It only grows in areas of high light and high water movement. I've scrubbed it off pieces of live rock and it grows back in a week. It doesn't seem to smother out corals, but aggressively grows on open pieces of live rock. Maracyn and Chemi-clean do not kill it off so I'm pretty sure it's not a cyanobacteria. Any thoughts?