I'm not sure what your budget is, but I switched my 90g over to a single Photon V2+ (48) ~$700 and have no trouble lighting anything I want in the tank. I've got LPS, SPS etc.. and they are doing pretty well. I haven't even ramped it up to anywhere near 100%. My PAR about mid-tank is 350. I also considered 2 fixtures, but I haven't seen where bridging the center brace with a single fixture has really impacted anything. The Photon has some nice features for ramping up/down and pretty easy to program once you get the hang of it.