Forget about wattage and think more about type of lighting, ie normal output fluorescent, compact fluorescent, VHO
, T5HO and metal halide. You can't compare a 175w mh
bulb with 4x40w=160w normal output fluorescent, even tho they are almost the same wattage.
A general guideline would be normal output fluorescent/compact fluorescent for lower light soft corals like mushrooms and polyps, compact fluorescent/VHO
for med light soft coral/LPS
coral and T5HO/MH
for med to high light corals like LSP/SPS