What's new
  • Happy Birthday ICMag! Been 20 years since Gypsy Nirvana created the forum! We are celebrating with a 4/20 Giveaway and by launching a new Patreon tier called "420club". You can read more here.
  • Important notice: ICMag's T.O.U. has been updated. Please review it here. For your convenience, it is also available in the main forum menu, under 'Quick Links"!

Dealing with negative pressure in grow tents

mtntrogger

mtntrogger

Member
Veteran
I am really curious how other peeps deal with negative pressure in tents. I am not growing at the moment, but am plotting my approach to restarting. I have a few tents left from my last time growing, 2 and a half years ago.
The one thing that I struggle with, especially in the flowering tent is how much the exhaust ventilation (blower) pulls in the sides of the tent.
I have used a speedster to control the speed of the fan, however in order to properly cool the tent the fan needs to be running high enough that it still pulls the sides in. I really wonder what other sort of problems this could have caused, such as herms (which I had alot of) from light leaks. I always 'test' the tents by having someone zip me up inside while its light outside the tent to check for leaks, but I could be missing small leaks ?
I have attempted several different 'fixes', such as really strong cords strung between the poles, and I ve even used 2x2's to frame outthe inside of a tent. Its all a PIA and I am not entirely satisfied with any thing that Ive tried so far.
Please share what youve tried , and what has worked best. Thanks !
 
WHIPEDMEAT

WHIPEDMEAT

Modortalan
Supermod
Veteran
with negative pressure controller synchronysed in and exhaust fans ?

[YOUTUBEIF]pJ3EkWsAlHY[/YOUTUBEIF]
 
mtntrogger

mtntrogger

Member
Veteran
Thanks shishka and Lrus ! These both seem like good options to explore. Intake fan seems like it might be the ticket. I would be worried that more tents on one fan might cause the tents to get hotter than I would want. Do you guys use filters on those intake fans ? Ive used one on my passive intake before. It was kind of spendy, if I remember right it cost me over $100.
 
M

Mr. J

Well-known member
You need to enlarge your intake or add more intakes. If your tent is trying to implode, then your static pressure is too high. Enlarging/adding additional intakes will also let your blower work more efficiently.
 
zachrockbadenof

zachrockbadenof

Well-known member
Veteran
excuse my ignorance ... i'm growin in a 4x3.5ft tent- under 2x315 cmh's and with '4' cheap led's for side light- flaps on both sides of the tent are open - one faces a window, and i have a fan blowing in cool air from the outside , and on the other side a fan is blowing in... so its like dueling fans , facing off at 4ft... the grow is fine.. what am i missing on neg pressure??
 
hush

hush

Señor Member
Veteran
If the tent is imploding, it's moving too much air or there aren't enough intakes. But if it's just barely negative, as is usually the case with a properly sized fan/filter combo running on a speed controller, then that's what you want. The slight negative pressure is what guarantees the 100% odor-free output. If I wasn't cleansing odor, I would actually go with positive pressure. But neutral pressure or positive pressure mean odor will escape.
 
shishkaboy

shishkaboy

>>>>Beanie Man<<<<
With the way I'm set up I only use the fan to scrub the smell...
The fan isn't really cooling the tent. I mean some heat does get vented out into my lung room but the air conditioner is what's really doing the cooling.

The way I do it I want as little air movement as possible through the filter to give more time to scrub that stinky air.

Imvho, an intake fan and out fan is kinda redundant, but I dont know how you plan to set up. I'm doing a sealed garden...

Where is the air that's being vented coming from?

In my situation it comes from the lung room through the cracks and seams, up through the cool tube and out into the lung room and conditioned.

Lather, rinse, repeat..
 
mtntrogger

mtntrogger

Member
Veteran
hush said:
If the tent is imploding, it's moving too much air or there aren't enough intakes. But if it's just barely negative, as is usually the case with a properly sized fan/filter combo running on a speed controller, then that's what you want. The slight negative pressure is what guarantees the 100% odor-free output. If I wasn't cleansing odor, I would actually go with positive pressure. But neutral pressure or positive pressure mean odor will escape.
Click to expand...

Thanks Hush
 
M

MindEater

Member
TakenByTheSky said:
The old general rule was intake should be double the exhaust
Click to expand...

That seems excessive. Don't these tents come ready to use, with properly engineered ventilation? Don't tell me everyone is cutting holes and wrapping shit in duct tape after dropping money on a "grow" tent.. Maybe I should start making/selling tents if that's the case!
 
You must log in or register to reply here.

Latest posts

Latest posts

Top