Quote Originally Posted by rhizome
Couple of observations-

Superthrive is pretty awesome, but you'll want to discontinue when you flip the lights- it'll extend flowering time, and lower final density. I wouldn't use a 1/4 tsp / gal on an extended basis myself- I use 1ml/g for veg, and save the big doses for transplant. Don't kick the bottle over- it'll reek for months.

You'll have trouble lighting 8x2.5 with a single fixture- I'd slap that 600 into a 5x5 room, ideally. To get good light intensity at the ends of the room, you'll need to use a mover. If you go for the mover, get the Light Rail- The slip chain designs never gave me any peace.

When ya talk about heat management, it's helpful to know what the reflector design is- this can have a huge impact.

If you're going to rehab some old hi-boy MH fixtures, go the bucks for good lamps ( Sunmaster Cool, Hort Blue). Also, remember to burn those lamps sideways! The hiboy design is great for Walmart- less so for your closet. Also, those things weigh a ton.
At the risk of sounding stupid Sideways?
Also, I had planned to make the room about 6 feet long by 4 feet wide, so would that work if I added another light- what would the minimum wattage have to be to make it work in that size room with the 600wHPS?
Thanks so much for your help!