innovative marine 40 aio

I have an IM Nuvo Fusion 40g and it’s like I’m growing macro algae in the back compartments because the light spills in there. Has anyone found a solution for this? With the overflow built on it makes it difficult to cover. Any advice?

In Colorado springs Innovative marine 40 All I one Includes most livestock except a few corals and a fish. Equipment included original return pump, brs dosers, jugs, brs titanium heater, hang back skimmer. Original media cannisters that comes with AIO system. Lighting includes hanging...