you dont have a hair algae problem. get some micro hermits. let your tank run a little longer, it may still be finishing the "break-in" cycle. algae is usually the last stage before things really settle into a balance. mangroves are good, but so is macro algae, like cheatomorpha. once you put a refugium on your system, they will help get rid of nitrates. if you are using dechlorinated tap water, you may be adding in nitrates and phosphates which is what the algae is using for nutrients.