2x 600w is the way to go. 600w is the efficiency sweet spot. You get disproportionately more heat going from 600w to 1000w. So you can get those 600w bulbs that much closer to the plant. Equally important is the coverage you get from 2 smaller watt bulbs vs. one large bulb. Think about it, with two bulbs you will have considerable light overlap and you will be able to light all corners of your tent. You'll find a link in my signature that will help you with your fan questions. The issue you need to keep your eye on is air leaks around the fixture and any attachment points.
bigsby Reviewed by bigsby on . moving into a tent I am moving from a closet grow to a 4.5 x 4.5 x6.5 grow tent. I have a 600 watt hps for flowering and that is probably too small so should I get another 600 watt light and air cooled hood which would give me 2 600 watt/12000 total or switch to a 1000 watt light and hood. If I did go with the 1000 watt light would 6" duct,fan and hood be ok or would I have to go to 8". I have 6" duct ,fan and hood now and I want to spend as less as possible but still have adequate light and exhaust. any help Rating: 5