Hey Dudley. Yes it's sort of a prop tank - more of a tank to house all my corals. I don't really have much. I figure without any corals in the 120, I can reduce the my MH lights.
I'm going to convert the pendent I got from you to a 150w and use that over my 20 gal (24"x18"x12").
The crushed coral is more for look. I might also get some kind of sand-dwelling goby in the future.
I'll just do as you say. I think my system can take a slight cycle if it happens. I was just concerned that adding the un-cycled substrate might exacerbate my algae problems. The algae is now under control, but I have to be diligent, or it might get out of hand again.