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Need a little help figuring out what setting I should have my exhaust fan on

The123321

Active Member
I have a 32x32 tent that is like 5.5 feet tall which I figure to be around 40 cubic feet. I have the 240w kingbrite quantum board led with the ac infinity 6" fan with filter. The fan has 8 speed settings on it and I run it on setting 1 and it pulls in the sides of the tent a little and keeps the tent around 77f and 60% rh on there. It looks like the first setting is like 44 cfm and setting 2 is like 88 cfm and setting 3 is like 132 cfm on up to the setting 8 on there. I am now thinking I may need to turn the fan up some to make sure it is moving the air in the tent enough to try to prevent mold in the tent on there. I would rather not turn the fan higher than the setting 2 or 3 if that is enough cfm though I definitely do not want mold in the tent on there.

I have read on different websites that say different things about how many times per minute you want to replace the air in the tent with your fan with from 1-3 times per minute or 1 time every 2 minutes on there. How many times per minute do you recommend? How much does the carbon filter reduce the cfm of the fan? Is it like half? I have the filter then a 90 degree turn with a few inches of duct to the fan then a 90 degree turn with a few inches of duct up out the top of the tent. How much do you think that reduces the cfm the fan is doing on the setting it is on?
 
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1ne eye

Well-Known Member
If it sucking the tent in some then its moving air, do you have a vent or somthing on the bottom to suck in fresh air for the exchange? The only time i crank mine up is if its getting to hot inside the tent. Yours at 77f sounds good. :cool:
 

Finesse69

Active Member
If you're worries about mold make sure you have airflow in the tent like fans moving the air in there as well this will also make stronger stems to support bigger buds. I usually have my ac infinities set on 4-5 with a 6" inch carbon filter and have yet to have mold at all in my grows so far.
Also make sure you have a open flap in your tent if youre running one fan so you have fresh air being pulled in as well
 

The123321

Active Member
Thanks. I have a 32x32 tent with the 6" ac infinity fan with filter on fan level 2 with 4 clip on fans that are like 6" in the tent with 2 fans right on the 2 flowering plants blowing the air through the plant pointed a little up and 2 fans blowing down from the top of the tent on there.
 

SamSmith

Well-Known Member
Unless the humidity is extremely low in the room you are growing in you really can't exchange too much air (within reason). I run temp/RH monitors in my tent to watch it just too make sure the RH doesn't go too low in veg. For flowering I run a 6" can fan extraction unit attached to my carbon with a 4" inline blowing in the bottom. I have to 4" ducted to the center of the tent. I run both fans on full speed along with (4) clip on fans blowing on the plants.

For odor control you don't want too little airflow across the carbon or it will not remove the smells efficiently.

too keep the sides of the tent from sucking in and eating up valuable space I fabricated clip on braces for the mid sections of the tent. They keep the sides from bowing in.
 

The123321

Active Member
Thanks. I have read that the lower the speed of the fan with the filter on it the better for odor control on there. Do you think the faster speed on the fan is better for odor control on there?
 

SamSmith

Well-Known Member
Depends on the size of the filter and the amount of odor you're trying to control. Too much flow and the air doesn't have the dwell time in the carbon to eliminate the odor. Too little airflow and it just sucks through the least point of resitance in the filter and the rest of it does little. The 6X24's flow a lot of air and can tolerate very high flow rates. The shorter cans are more restrictive and don't flow as well. You may have to play around with it a little to tell but I would error on more flow than too little.
 
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