scrub your rocks with a toothbrush, even if you don't have any hair algae present on the rock, it'll still knock anything that might become algae. Then do a 10-15% water change. Doing water changes will consistently bring down your phosphates. Since your tank is relatively new, it's prob. just the die off from the LR.
Also, your tank is going through the "new tank algae cycle", so look forwards to more algae. :) Don't let it discourage you. If you fight the good fight you'll eventually win and not really have to worry bout it again.