Venting Questions

I have asked a few questions now and got some help so here I am again. I am building a 4x4x5 flowering box with a 400 watt HPS and was planing on venting it with a 3 speed shop fan up to 300 cfm and was wondering if that is to much or not enough and a moutable oscillating fan directly on light fixture and attached ballast. I am going to put 2 vents on top and one on bottom in addition to blower that is going on the bottom. Do I need to fan out top vents or will the blower be enough top push it out. Help please.

Socalstoner said:

I have asked a few questions now and got some help so here I am again. I am building a 4x4x5 flowering box with a 400 watt HPS and was planing on venting it with a 3 speed shop fan up to 300 cfm and was wondering if that is to much or not enough and a moutable oscillating fan directly on light fixture and attached ballast. I am going to put 2 vents on top and one on bottom in addition to blower that is going on the bottom. Do I need to fan out top vents or will the blower be enough top push it out. Help please.

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try out the different speeds and see which one works best. 300 cfm in a 80 cf area might be something like a windtunnel, i dunno how u have it sealed up or anyhting. a rule of thumb is you want to change all the air in the room at LEAST once every 5 minutes. personally i would use the fan on top to suck air instead of push it, usually more efficent that way. if your sucking the air out it will create negative pressure in the room thus air being sucked in from the bottom without having the push it in. hope this helps.