A 400 watt would probably do just fine and be much less problematic to vent.In that space , a 400 watt HPS should do just fine. The heat differential will be worth it in my opinion.
Deejay2163 Reviewed by Deejay2163 on . 400w HPS or 600w HPS? im growing in a 4'x4'x6.5' grow tent. i currently have four plants doing very well under a flourecent light in veg state. In a few weeks i start flowering, now what would be idea for my 4 lovely ladies, 400w hps or 600 hps given my tent size? Rating: 5