IM 20 gallon drop off. 15x20 foot print. Might need one of those focuser reverse diffuser things I saw they make for them.It's still pretty bright even at 1%. How nano is the nano? At 2.25" above the tank it hits the top of the front and back panes of the 150g.
Holy cow, 2 1/4" inch... that's almost a 180° spread.

