Need advising on carbon filter/fan

so the plan is this:

hlg 100 v2 3k
27x27x63 tent
2 autos

i need to have almost 0 smell. preferably zero…

any help is greatly appreciated.

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I like ac infinity fans. I have a hydro charcoal filter. Keep negative pressure to ensure all air is filtered. Oh and Welcome to the forum. Experts will be along to steer you in the best possible direction.


Tha AC Infinity fans are the ticket and a good carbon filter.Worth a little extra money for the fans,they perform extremely well.


I use 6 inch carbon filters they work well. Just remember high humidity makes them fail.


I’m in a 2x2x4 and run the AC Infinity 4in fan and a g hydro carbon filter. Absolutely no smell as long as there is negative pressure as stated above!
Happy growing!


What method do you use to accomplish the negative pressure?

You mean negative pressure inside the tent correct?

So, the air pushing in needs to be greater than the air pushing out, while still providing fresh air circulation?

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Air out has to be greater then air in for negative pressure

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It’s the opposite. Air going out needs to be greater than air coming in. A tent’s walls should pull in as a visual indication of a bit of vacuum inside the tent. The negative pressure inside the tent prevent air from escaping the tent aside from that being pulled out intentionally.


I’m running the exact same setup and have zero complaints!

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Same here!

So I’m 100% new to indoor tent and requiring ducting and ventilation.

I’m truthfully about as new to cannabis growing as possible. Very minimal experience outdoor that did produce, not much effort was put into it.

Is there an explanation that could be provided of how to accomplish this?

My understanding was a fan connected to a duct that runs through a filter to the outside of the tent?

There are options with carbon filter placement and it doesn’t matter which side of the fan you put it on as long as it is placed in-line with the output system.

Here I have the input at the bottom of the tent. This is done to provide for better air circulation around the plant itself.

The output is at the top of the tent as pictured. It should be near the top since you will want hot air exhausted from the tent.

Most fans are adjustable. You can pull a bit of a vacuum on the tent by having the exhaust air turned up a little higher than the input air. I calibrate how much the sides get pulled in on a closed tent at various speeds. Yes, you do need to exhaust air to the outside of the tent. It defeats the purpose of odor mitigation as well as potentially causing heat problems if not.

So what I’m looking at here is a hole at the bottom with flex duct running outside to a hole at the top with flex duct connected to a filter, connected to a fan, connected to more flex duct going out of another hole inline to the opposite side of the tent?

Is that right? Pictures are always screwy to get a whole image of what’s going on.

I think the flex duct at the bottom is intake air only. It wouldn’t make sense to me if it was reconnected at the top. As to the set up at the top of the tent, You have the carbon filter getting air pulled through it by the inline fan which is then pushing the hot air through the gray flex duct and out of the tent. Heat rises so you want your point of extraction to be at the top for the best results.

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