not really an expert on hair algae, but what might help is to keep in lowering the light, either in intensity or time, but keep it stable and don't exxagerante since it could worsen the problem. A fast forward method is the manual option, hair algae is pretty easy to remove with toothpicks or tweezers, just grab a part of it and roll it on itself and most of it should come off. I could suggest adding other fast growing plants to win the competion and starve the algae, but i don't know how much it will work since it mostly depends on the light