I have rocks in my tank that are forming beautiful coraline algae, and others tht are a shade of green and brown, is this "bad" algae forming?
I wouldnt say very fast, maybe try turning the lights off for a couple of days?
Not near a window, lights are on from 8am-8pm, blue lights start at 8am, white lights kick on at 11am-5pm, blue lights kick off at 8pm