Andee they're probably not going after the hair algae because they're so much other food available right now. So I imagine your tank has already gone through the complete cycle??. If it has just keep up with some water changes, this will help you get rid of the nutrients that are still coming off the dying portions of your rock and feeding the algae. Algae blooms at this stage of a new tank are pretty common.
On new tanks you will get to experience the fun of the different algae blooms. All normal on new tanks. You will go through phases: diatoms, green, hair, etc....
Question, did you start your tank out on RO/DI water or tap? If you started with tap you will experience more problems in the beginning with algae blooms then if you had used RO/DI water...
what supplements do you have in mind? I wouldnt think you would need anything other than a Ca addition at this point. As above the hair will go away with time, just be patient
Definitely choose your supplements with care. Many will hurt worse than they help. Keeping your alk and pH levels consistent will be of the biggest help to you right now, but make additions and changes slowly, so as not to get a yo-yo effect going on in the parameters.
Also, take readings late in the day so you get a true level; ph especially can drop overnight.