I've had my fights with hair algae before and the only success I've ever had is to totally eradicate all of it by scrubbing it, which isn't easy. Hope you find an easier way.
well the pics look like a brown stringy algea .. and to me if it wa on a rock or on a piece of wood it to me i would kinda like it cause it looks natural.. kinda like what you would actually see in a river or something lol