Not really convenient for everyone, but I cooked my live rock. If you don't know what that is, it's putting your lr in a dark tub for 6 weeks and doing 100% water changes each week and scrubbing, dunking and swishing the rock in separate buckets of saltwater each time you do a water change in that 6 week period. It doesn't actually involve cooking your rock with heat. I'm not sure why it's called that. It's more like recuring it and making sure it's left totally in the dark. This process is supposed to rid your rock of phosphates. Downside is, it's a major pain in the a** and you really need an RO/DI unit to make sure you have high quality water for the water changes. You have to make a crapload of water. It came down to this for me because nothing else was getting rid of my hair algae problem. If I pulled it out, it would just grow back. My snails and crabs weren't eating it worth a crap and the lawn mower blenny wouldn't touch it either and ended up starving to death. Long term results, I don't know yet. My rock has only been back in my tank for a month and so far so good. People swear by this method though so I though I'd give it a try. I'd only do this as a last resort, if nothing else works keep this in the back of your mind. Good luck, hair algae problems can be enough to pack it in and get out of this hobby. It almost was for me.
Oh I forgot to add another suggestion, buy some ROWAphos phosphate remover. That's the best phosphate remover out there. Try this in addition to everyone else's suggestions. It might work out for you.