Follow the instructions on this blog pertaining to algae and it should fix your hair algae issues one way or another:

http://www.aquariumalgae.blogspot.com/

I didn't dose any chemicals, just manually removed as much as I could, and turned off the lights for about 2 days. I added in a powerhead to increase water flow over the area where the hair algae was growing. It significantly reduced most if not all of the remaining hair algae. I still see bits here and there but it doesn't bother me. Algae is part and parcel of a normal fish tank. Sometimes it can be an eyesore but if it is not affecting the tank inhabitants adversely, I'd just live with it, and try to control it the best I can.