20w/cu. ft zone ping:
But to be honest I do have a couple in the 40w/cu.ft zone as well...
here is an example:
I think both are good looking and have good color.... I have one in the 20w region that is more colorful then either pic... so Ill stand by my rule of thumb.
But again, thats all Im saying it is.... a starting point for wattage calculations based upon good equipment selection.
Every newbie wants to know how much light they need... this is the standard I use with decent results imho