tent ventilation setup?

If I have my carbon filter inside the tent connected to ducting to hood to ducting going oudside the tent to fan would that create negative air pressure?
the tent has vents to bring in fresh air but if I opened them that would bring the smell out of the tent right?

Yes that will create negative pressure in the tent. Air goes through scrubber, through duct, through hood, through duct (out of tent), and through the fan. The fan should be expelling clean air.

If you have the fan running in that fashion then you can open the vents on the tent and because it is under negative pressure air will leak INTO the tent, and never the other direction.

guy incognito said:

Yes that will create negative pressure in the tent. Air goes through scrubber, through duct, through hood, through duct (out of tent), and through the fan. The fan should be expelling clean air.

If you have the fan running in that fashion then you can open the vents on the tent and because it is under negative pressure air will leak INTO the tent, and never the other direction.

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How do you know it would create negative pressure when you don't know the necessary details...?

With that being said, professorkush, what is the CFM rating of your fan, how big is your tent, and what is the size of your carbon filter? These are the three key factors to calculating whether or not you are exhausting correctly.

Auzzie07 said:

How do you know it would create negative pressure when you don't know the necessary details...?

With that being said, professorkush, what is the CFM rating of your fan, how big is your tent, and what is the size of your carbon filter? These are the three key factors to calculating whether or not you are exhausting correctly.

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What details? That is how air pressure works. If he sucks out it will create negative pressure inside the tent. I made the assumption he is using a fan large enough to connect to the size ducting he is using. Don't use a duct booster fan.

^^ and even if you did use a duct booster it would still create a negative pressure. You don't need much air flow to create negative pressure... just a little is all it takes to keep the room smelling fresh. Keeping heat at bay is another story.

the tent is 5x5, filter is 550 cfm, and the fan is 440 cfm. I was just a little unsure of principles of the air flow in the tent. Thanks fellas

thatsmessedup said:

^^ and even if you did use a duct booster it would still create a negative pressure. You don't need much air flow to create negative pressure... just a little is all it takes to keep the room smelling fresh. Keeping heat at bay is another story.

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Yeah it would be negative, but I don't know if the quantity of air flow would be sufficient. Probably would not be removing enough heat like you said.

Your set up sounds fine. If you zip the tent up you should be able to check for negative pressure anywhere there is an opening. Use a candle or lighter to verify air it getting sucked in at those openings. As long as you don't smell anything outside of the tent though I would say you are good to grow.

ur room is only 200cf anyway so a 440cfm is plenty. i use booster fans on all my tents but dont run carbon filters so there is no air flow restrictions.

Negative pressure is a certainty! That fan if very powerful for a 5x5 you may need to experiment to get the pressure down, if it is imploding your tent too much.. also if your hood is sealed or not depends how much pressure as well.