2 will be more expensive, since se 1000 is for 4x4 with co2, other wise all others are saying their  800 watt is good for 5x5, since i think spider is better than mars or any other, 1000 watt should do the trick, plus i have an ac inside the tent, on wooden stand it takes 2 foot atleast, and anything under or very close is definitely dying , killed 2,

are you using se7000