Water flow, and stop feeding quite so much. I fought with this for 2 years and was almost ready to empty my tank and throw it in the dumpster. I had tried everything, pulling, scrubbing, chemicals, nothing worked. I mean I would get a little relief but then it was back and most of the time worse than before.
To give you a little info on my tank : I have a 150 gal
tank with about 250 lbs of rock 4 or 5 small to med fish, Current usa 5 ft lights with 10K and duel antics, had a emperor 400, a penguin 300, a Mag drive 12 feeding from the sump (29 gal
), thought that was a plenty plus I had 4 or 5 ph's in the tank as well. Got tired of the garbage with the hair algae so I got my spare mag 9.5 and put it in 1 end of the tank pointing across the back (on 15 min off 15 min, and off at night), replaced the 400 and the 300 with 2 new penguin 350's (best investment in a filter lately), continued to pull out the big stuff (don't scrub it will make it spread). Today I ordered another 9.5 to put oin the other side of the tank so I can alternate between the 2 (kinda like creating a current).
Since doing this my toad stools have gone nuts (I'm now up to 10, 2 originals and 8 "sprouts" (if you can call them that), my hair algea is GONE. I did loose my yellow tang but I think it was sick, just looked funny but I got it out of the tank.
The only problem with my setup is with that much current flow your sand moves around a bit (if you point the 9.5 at the sand you will have sand covering everything (and I do mean everything))
If you need any assistance feel free to ask. I hope my info has helped you