Inline Fan Cfm Question

[MissBotany]

currenlty I have a 6” 442 CFM inline fan hooked up to a carbon filter at the top vent hole of my flower tent. I’ve been keeping the tent zipper partially unzipped to create negative pressure but I want to stop doing that. So my option would be to hook up a 4” inline fan to one of the bottom vent holes. Would a 4” 190 CFM work or do I need a fan with a higher CFM?

Thanks,

S

 

[Monster762]

currenlty I have a 6” 442 CFM inline fan hooked up to a carbon filter at the top vent hole of my flower tent. I’ve been keeping the tent zipper partially unzipped to create negative pressure but I want to stop doing that. So my option would be to hook up a 4” inline fan to one of the bottom vent holes. Would a 4” 190 CFM work or do I need a fan with a higher CFM?

Thanks,

S

You should have screened vents. Just open them and that 6 inch should be all you need. I’m running a 4x8 on a 6 inch through filter. Passive intake. In order for that much air to get out it has to be coming in. How big is this tent?

 

[Monster762]

You should have screened vents. Just open them and that 6 inch should be all you need. I’m running a 4x8 on a 6 inch through filter. Passive intake. In order for that much air to get out it has to be coming in. How big is this tent?

I open all low vents then exhaust out the top. I have duct barely entering tent sealed and fan is outside strapped right to the filter. No room for all that mess inside.

 

[MissBotany]

Thanks for the suggestions.

It’s only a 36”x36”x72”
There are three air vents and I want to say I tried opening all three vents with everything else closed up and the fan sucked the tent in way too far.

I can live with how I have it it now but I didn’t want any light coming out of the tent. With the front zipper open about about half way, a lot of light escapes.

 

[Monster762]

Thanks for the suggestions.

It’s only a 36”x36”x72”
There are three air vents and I want to say I tried opening all three vents with everything else closed up and the fan sucked the tent in way too far.

I can live with how I have it it now but I didn’t want any light coming out of the tent. With the front zipper open about about half way, a lot of light escapes.

Oh. Yeah you got overkill for that tent. You’d been good with a little 200cfm. Maybe an intake might help but I think it’ll still be sucking the tent in.

 

[MissBotany]

Oh. Yeah you got overkill for that tent. You’d been good with a little 200cfm. Maybe an intake might help but I think it’ll still be sucking the tent in.

Yes, I agree. Definite overkill but there is absolutely zero smell even with drying buds in the room! I must have been reading grow room set up guides for people doing large grows!

 

[Westie]

If you do not already have, a fan speed controller could help you regulate/balance the pressure. Helped me manage temperature as well.

 

[MissBotany]

If you do not already have, a fan speed controller could help you regulate/balance the pressure. Helped me manage temperature as well.

Good thinking. I’ll see if that’s an option for this fan.

 

[Westie]

Good info here on the THC farm.
https://www.thcfarmer.com/community/threads/buying-the-correct-fan-speed-controller.60640/page-2

Hopefully a cheap controller will do the trick. For me, I tried both.....I needed a variac because the cheap controllers did not slow the fan down enough for my needs.