30 cubic feet?

That's volume... Rasta, how much square feet do you have on your grow room?

length x width = xx ft^2

How far away is your light from the bottom of your grow room? From the average top of your plants? Top of your pots? I don't know... get the best reference point.

Once we have that, we can use that nifty insverse square law to determine how many lumens you've got going...

As to how many lumens per cubic foot... Again, it should be 'square feet'. Cubic is volume.

I think that with something over 7000 lumens per square feet you'll be pimpin' .

-turtle420