I think
WPG is a bad myth
I agree. It also depends on the type of lighting. Some lighting (such as
MH) penetrates the water better then others (like
CF). This is why a 150watts of
MH seems brighter then 150watts of
CF. If you are looking to add a few corals to your tank, decide what you want and build your lighting needs around them.
CF will do just fine for most soft corals, zoos, polyps,
LPS, some
SPS and even some anemones. If you plan on keeping higher light
SPS corals, clams and anemones you should consider
MH. The down side to
MH lighting is it's cost, possible increase in algea production, possible increase in tank temp and increase in electric bill.