Hair algae problems

[ichthyojason]

Anyone have any advice/suggestions on getting rid of my hair algae? To be completely honest, I have no idea why I am getting any hair algae, with the possible exception of maybe a bad supplement. I was having some nitrate issues, but I upgraded the skimmer and added a fuge. My Nitrates and PO4 was just tested and came out at 0 for each. I also have put on a Phosban reactor with RowaPhos, as well as put in mangroves. Nothing has seemed to help other than just siphoning it off. So, I guess I am looking for any other biological means of removal. I bought a Rabbitfish, but am a little concerned that he may turn to eating the corals instead. The tank is a 240, so I have room to add some different things. Was thinking about getting an urchin. Anyone have any experience with these and hair algae? Also maybe a tang - I only have blue tangs that don't want anything to do with the stuff. sailfins, Koles, Yellow, Scopas? All advice eagerly awaited.

Oh yeah, the only other thing I can think of would be the lights - which are under a year old (though I am planning on ordering new bulbs now), but if my No3 and PO4 are zero, I can't imagine why the lights would matter?

Thanks