I gathered advice from many posts on it... Heres what I reccomend...
Cut back on lights.(most important) It wont hurt to go a week at 6-8 hours a day. Even cutting back from 12 to 10 hours a day will help.
Cut back on feeding, and bioload. If your overstocked, your doomed! Feed less, and feed flake instead of frozen every other day.
PROTEIN SKIM!! Just mechanical/bio filters wont do you much good. Get a protein skimmer.
REFUGIUM! The macro aglae's really do help!
Change your water. Get a siphon and suck up some of that nasty stuff from the bottom of your tank. I change 5% a week, or 10% every 2 weeks.
USE RO ONLY!!! tap water has too many contaminants that make hair algae grow and spread.
Get plenty of circulation all over the tank. One thing that helped me was putting a power head behind my rocks at the bottom. This prevented food from decaying down there and getting stuck in rocks. If you notice, the places with hair algae are the places where crap gets stuck on your rock.
Obviously get a suffecient clean up crew
Lastly, some might not reccomend this, but despirate times call for desiprate measures. BTW, I did this awhile ago to get rid of it, and it hasnt come back. Just so you know I didnt do this then take the pic, I promise you my hair algae is gone for good, and been gone for about 2 weeks w/ no sign of return...
Take a turkey baster or a clean tooth brush or something and scrape the crap out of the hair algae. Do this when your siphoning water, or use a net to remove all the floating removed algae.