Great suggestions, everyone. As far as par38 lights go, do you mean something like the Reef Radiance DM-12e, or is there another product that you would recommend?
I had both a AI Nano and a Kessil A150 on a Biocube (different times). I would highly suggest the Kessil due to shimmer and simple appeal. My AI Nano was just too bulky for the little cube.