I think 1 would be perfect! I have 1 over my Elos Midi, 36 gallon, and I'm currently slowly moving my stock from my tore-down Nanocube over. I have the light programmed on Natural mode at 30% intensity - 100% is Brrr-IGHT!. Now, if you have a typical 29, I imagine it is 30" long, so you would need to put your low-light corals on the sides, but those tanks aren't very tall so I would think practically anything, from clams to hardy SPS (like Montipora sp.) could go on the sand right under the light (more demanding SPS and T. crocea higher up). Just 2 cents from a new Radion owner.