Lumens or WPG?

[fish for life.]

Obviously wpg is a measure that has a rather large room for error. Depth and surface area have more to do with how much light your critters are getting than how many gallons are in your tank. Of course there is a relationhip between depth/SA and gallons but it is not consistent with all the shapes and sizes of tanks out thier. I am a Math Teacher and wonder if there is a better equation than wpg to measure light? I have heard of lumens, but I am no electrician?!

 

[fish for life.]

So are lumens or watts a better measure??? If we choose between the two, the other variables are depth and surface area. So... I think we can come up with a better representation than wpg. <img src="graemlins//confused.gif" border="0" alt="[confused]" />

 

[fish for life.]

I am just trying to figure out what light measurement is good. Found a great thread using LP/SA. Lumens x par/sguare feet of tank. It seems wpg has very little meaning, but is still used to talk about how much light a tank has. I like the LP/SA it makes sense.