Ahhhh, the dreaded red hair algae. I hate this stuff and very difficult to eliminate regardless of your assumed nutrient load. I've heard of Diadema urchins consuming it along with foxface fish, but not as a priority and depending on actual algae specie I'm sure. Other than pulling it out, using a toothbrush and hose combination, and/or just allowing
cyano to smother it; I've had few promising solutions to ridding the stuff, but have heard of others going to the extent of using a small butane torch on their rock (not sure I like that idea, but when desperations rears its ugly head)....