oh i might mention one other thing 2 you that i really really wish i had done.when i bought my tank and regulator,i think for $150 a piece soooooooooooo total being $300 plus tax. i could have got a co2 burner that runs on natural or propane.in my opinion much much more effective.that way your burner can run your whole lights on period and even if your exhaust takes most of it out the window a lot of co2 would be left behind.my friend does a sealed room with ac and a constant burner running and is pulling 2 to 3 times the weight i do.just something to consider i think c.a.p auctually makes a pretty cheap 3 burner for like $560 bucks.