Don't know of a fish that eat hair algae. Turbo snails I have heard will eat it, I have yet to see it. I brought my refugium on line last week and I am hooking up a phosban reactor tonight and will let you know if it helps. Unfortunately I won't know if it was one, the other or both that did it. My salifert test kit has always read 0 but according to the lecture I went to at MACNA, the test kits available here don't have low enough readings to work for us.
My $.02