Thanks!

The size of the "room" will be the garage which is 20x25 ft.

It's .5g per watt usually?
I'm thinking bob is going to be using 4000 Watts - HPS with Digital Ballast
Thats about 2000g = 4.5 LBS....

Now with hydroponics and good neurts... shouldn't that .5g per watt be almost .75 to 1g per watt? which would be around 9-10LB.