It is probably the most harmless macroalgae. I had a little show up for a short time in my office cube. I was sad when it got eaten or dissappeared. It is a pretty algae. I agree that you could outcompete with a refugium. I would try outcompeting with that algae in the refugium just as badbabyfry suggested. Transfer a few pieces from tank, add herbivores, and hopefully the display will get mowed as the refugium grows out to take over.