Just wondering - Is that a dorm room? I just noticed the painted concrete walls....
Nice tank coming along by the way. Need to get rid of that hair algae before it spreads too much. Get control of your nitrates and phosphates and algae won't be a problem. You may even have to keep your lights on only four hours a day until it clears up. It seems that right now because you don't have any fish and the tank is still kind of new - that you might want to check your top off water to make sure your not adding additional nitrate/phosphate into the system.