[tang daddy]

IMO 400w mh for my old 65g was enough light to grow sps it all depends on what kind of sps you are trying to grow if digi and monti t5 is good. If you look at the euro tanks they all run t5 but keep in mind that they run 8-10 t5 at 84w ea that's comparable to us running 2x250 or 2x400 with t5 supplementation I currently run 1000w for a 120g and find it suffiecient also if you run t5 for your tank and wish to have sps thrive then you need awesome flow and to feed the sps with ultralith or similiar types aswell as prodibio.