With a 600w if you do good you should be expecting 1/2 grams per watt of light. So 300 grams. Some nutrients and a addon or two wil get you there. That's a good size light for your space. i have a 1000w in a 4x5x8. over kill I know but just got a lumateck dial a watt ballast. So I maybe will turn it down to 600 and see watt happens. If its below a pound it's back to overkill.