i had a scrog cab with 4 42 watt cfls 1 65 watt cfl aquarium strip and a 125watt vitalume cfl, yeilds were 4-4.5 oz or .33-.36 gm/watt but with hps i have no trouble getting 1gm/watt with my 400 and my 150. you can get a 150hps for pretty cheap(under 50 bucks) and i got over an ounce more with 150 watts of hps than i did with 350watts of cfls.