We just went through an awful hair algae problem.  We tried everything mentioned above with no luck.  I removed rocks and scrubbed, removed rocks and let them die, sea hare, lawn mower blenny, urchins, all kinds of crabs, you ge the picture.  I was about ready to just take down the tank.  After 9 months, we tried a fox face and he had the whole tank picked clean in 5 days.  I don't think every fox face will do it, but you may get lucky! Just put that one on yor list of ideas if you get desperate.