show me your fans!! setups, mounts, hangers, filters, etc...

god damnit, a spelling mistake in humidifier. thats gonna bug me all day.

Thusly:



You may not be able to see clear, but that is a quantum board mounted right below the fan and filter.

yeah I can see the light there. interesting way of hanging it inside.

so it looks like your fan and filter are inside, shooting non stinky air right outside. so barely any ducting needed which is not only cheaper, but more airflow. (random info... they taught us in pipefitting school that a 90 degree elbow is the equivalent resistance of 40' of straight pipe when dealing with fluid/air movement)

CF89 said:

yeah I can see the light there. interesting way of hanging it inside.

so it looks like your fan and filter are inside, shooting non stinky air right outside. so barely any ducting needed which is not only cheaper, but more airflow. (random info... they taught us in pipefitting school that a 90 degree elbow is the equivalent resistance of 40' of straight pipe when dealing with fluid/air movement)

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Yeah clean air right out the side. It's only about 6 inches of duct, maybe 8

I like your hanger system too. I need to figure out a way to mount to the tent rails easier than my carabiners that dont open enough for the bar to go into.

CF89 said:

I like your hanger system too. I need to figure out a way to mount to the tent rails easier than my carabiners that dont open enough for the bar to go into.

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I got these S hooks from the dollar store. They work great. Also any cheap chain from home depot. A must when hanging lights in a tent

My exhaust is at the highest part of the ceiling, sucks air through the carbon filter then pushes it outside. Negative pressure draws fresh air in through the passive intake which is the hole at the back with a backflow preventer on it.

On each side of the room I have an ocsilating fan, and a 4" inline fan also draws air from near the intake and blows it through a piece of 4" perforated ducting on the floor to keep air movement below the canopy.

You can just see the 10" Qmax fan attached to the filter in the top left corner of the room.

awesome. what a room!! wow. more good ideas.

the bottoms of my smart pots always seem wet... so I want them on a mesh rack of some sort too. I like your airflow from the bottom idea too!! im going to do that too.. why not? airs coming in anyways. may as well come in from the bottom.

seems like carbon filters always go inside the tent... good to know.

The filter fan combos seem to be a bit more efficient pulling rather than pushing through the filter. And airflow below the canopy is important. I dont use the air directly from outside for that though, it gets chilly in Canada in the winter so I blow the intake air directly between the lights and the top of the plants where the most heat is trapped. Then I draw this moderate temperature air from above the canopy and duct it below the plants using a seperate small fan. Works really well at keeping the whole room an even temp, and keeps all the leaves moving gently which increases gas exchange around the lower leaves.

This is the best thread i know of that shows all the proper ways to ventilate tents or rooms.

I hope the link works. Icmag is weird for links.

Here’s what I’ve done...suction out of the tops of two 4x4 tents, via 6” centrifugal fan, via home made junction box, then out to filter. All the fans, filter outside tent. Has worked great for a few years.

These are pics from start of the season... This is version 1.0 i have since been on 3.0 which started as 2.0 then changed. But essentially in the end it will have a new heat recovery unit w/ bypass for summer. i built housed inside the box which will lead to a uv chamber which will be for the inlet fans. and will expand to an 8" return that connects all the tents to balance it out for positive pressure. Going back through a merv 14 charcoal filter pushed back under and into the main chamber. that will now be standard merv 14 filters. making it more interchangeable on filters so i dont have to duct tape for fitting. All connecting my labyrinth of tents.

so essentially will have mite, pollen, fungis scrubbing. and all the other stuff up to merv 14 with UV


But this was the early prototype i still use that lead to me figuring out my needs. using i believer merv 5 filters i got for $1 on clearance.

Curious what those two clear empty soda bottles are for? Great McGiver’g...

Dan789 said:

Curious what those two clear empty soda bottles are for? Great McGiver’g...

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I was doing flow testing of each fan and was testing with a smoke machine. before i expanded to 4 fans and 2 liters fit perfectly over 4" fitting if you cut a small slit. essentially giving you air tight. I Believe the pics were taken when i was testing those 2 fittings for leaks. it changed to 4 out 1 in. In that photo was 3 out 1 in setup. went to 6" return. new one will be 8"

Goal is to limit risk of pollen exposure since i like to make seeds. i dont want tents crossing over. where i have em now controlled by a raspberry pi. works out really well. super efficient. not sure if the heat recovery unit i made will keep the efficiency of the air flow. but hopefully it recovers enough heat in the winter to make up for it when needed. Still worried about going to merv 14 with these fans. but i think ive worked it all out. Goal really is to keep that same foot print but go vertical as much as i can.

damn thats awesome man. wow. every pic I see just gives me more and more ideas.

I like the concept about the cold canadian air... good point. the basement gets pretty cold. not sure if I want to be blasting air thats 15C at the plants. but with that much vent tubing I may need another fan.

which makes me wonder... I have an inline 4" and an inline 6"... which should be the intake and which should be the exhaust?

3x3x6 tent is 54 cubic feet. and I want to evacuate that 3x per minute. so I need a 150cfm fan exhaust?

and its saying that the intake fan should be 2x the exhaust fan?

my 6" fan is good for 240cfm


"ANY 6" exhaust in ANY size grow space using the proper amount of CFM's to successfully exhaust will require only an 8"x8" hole (or equivalent thereof in smaller holes) for passive intake?"


seems like im gonna want the 6" as exhaust to not only overcome the carbon filter resistance but to create a negative pressure.

right now theres only an intake, and no exhaust, and the tent is bulged out like a balloon, shooting weed smell all over out of every crack. so if I had a massive exhaust and created the exact opposite effect, it would draw air in like a giant vacuum, and the ONLY air leaving the tent is through the 6" carbon filter.

CF89 said:

3x3x6 tent is 54 cubic feet. and I want to evacuate that 3x per minute. so I need a 150cfm fan exhaust?

and its saying that the intake fan should be 2x the exhaust fan?

my 6" fan is good for 240cfm

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That's a lot of air exchange, possibly too much. You want to aim to fully change the air once every 2-5 mins.

Personally I'd run a 4" inline fan with a speed controller on the exhaust and a 6" axial fan on the intake, or if you are filtering the intake you could just run a second 4" inline with speed controller on the intake end as well. That would be closer to ideal, and you could use the speed controllers to balance the pressure in the tent.

Dirtbag said:

That's a lot of air exchange, possibly too much. You want to aim to fully change the air once every 2-5 mins.

Personally I'd run a 4" inline fan with a speed controller on the exhaust and a 6" axial fan on the intake, or if you are filtering the intake you could just run a second 4" inline with speed controller on the intake end as well. That would be closer to ideal, and you could use the speed controllers to balance the pressure in the tent.

Click to expand...

bigger fan on the intake than the exhaust?

so if my tent is 54 cubic feet and I can use 2 mins to change it, I only need a 25cfm fan? that seems way too low. im super confused and backwards now.