If you decide to restart, I would get high quality live rock, your corals will retain the hair algae and you will be seeding the tank with base rock and hair algae. If you go with good live rock the algae and bacteria's will already be present and will be able to out compete the hair algae for nutrients. I take rocks with hair algae out of my 29 and put them into my 100 for my tangs to clean up, I'm not worried about it spreading.