As to directly answer your question, my fighting conchs made quick work of hair algea before they expired.
I am just coming out of an unbelievable hair algea bloom, and I did that by 1.) cutting my lighting time in half 2.) Doing an all told 100% water change a week 3.) Using a mesh bag of phosguard to filter my return water and 4.) cut feeding to every third day.
65gal drilled Reef (3'x1.5'x2').
1 Powder Blue Tang, 1 Yellow Eyed Kole Tang, 2 Ocellaris Clownfish, 1 Talbot Damsel, 1 YWG, 1 Red Honey Damsel.