Ok i read the sticky but i must say that im even more confused, as i really dont know how im supposed to achieve the right type of light using this formula. here's my example:
tank dimensions: 48x15x18. depth x 2 = 30. so, 48+30+18 =
96
now, i have a Powerglo T5 bulb, 18,000k, 54w, 2150 lumens. just a scenario, if i were to run three of these lights (162w, just aboug 3wpg), i would have 6450 lumens.
using the forumla in the sticky, 6450 lumens / 96 gives me a value of
67. according to the sticky, this is low to moderate lighting; fish only or low light plants.
so, if i were to use this bulb i would need about 8 54w bulbs to put me in the moderate to high lighting category. this would mean 432w of electricity!!!!!

is this correct?
im aware that i may be getting a low figure because the 18,000k bulb has a high K rating and low lumens output. would it make a big difference in lumen output if i were to use something in the 6000~10000k range? do you know what the lumens output of a 10000k T5 bulb is? i only have the box for this 18000k bulb so this is why i used this bulb as an example.
help me out here! thx