AC infinity Fan to Blow or Suck?

This is my very first grow with proper equipment and I’m down to just my air circulation setup before I am all set.I’ve got some black widow seeds germinating now and things are looking good!
I’ve got a 4x4 from AC infinity with the T6 inline fan. The temp of the room the tent is in stays around 75 and 45% humidity. I’m going to have a CO2 bucket suspended in the tent and I’m concerned that if I put the fan at the top, pulling hot air out, I’ll also be pulling the majority of my CO2 out.
Is it best to have passive intake and forced exhaust, or should I have forced intake and passive exhaust? Keep in mind I’ll have a couple oscillating fans inside as well. Any help is much appreciated!

@Rigs50 passive intake and active exhaust will work fine using C02. Just get a temp/humidity controller and have it only kick the exhaust fan on when temp exceeds between 85-90f with added c02 or when humidity goes over 70% in veg or over 40% in flower.

It will save money on electricity not having the fan running 24/7 and it will allow both environmental and added c02 to build up in the tent.

It also helps to hang the C02 on the opposite side of the tent as the exhaust and just hang it a few inches above the canopy with a fan on low behind it so it spreads the c02 around and lets it circulate around the plants.

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It wouldn’t be more beneficial to allow the filtered air from the intake to pressurize the tent and force the hot air out through the top?

This is my first grow with “proper equipment”, so I’ve never had things like an in-line fan, CO2 or even a decent tent, so some of these are a bit of a learning curve.

@Rigs50 that is a positive pressure setup and it works great for building up environmental C02 from the intake but it also builds up heat more so if you run a positive pressure you will need good fans and maybe an ac too. This will also push extra C02 out of the grow tent and you will have a hard time getting the C02 ppm over about 500.

When you run C02 you want to have a grow area as sealed as possible so C02 can actually build up. Negative pressure and positive pressure will both pull or push the C02 out.

Either way you should run a controller so intake or exhaust only kicks on when needed so your environment can stay neutral and allow the C02 to build up without pushing it out or exhausting it all of the time.

If you have your tent in a sealed room that allows c02 to build up you’ll be fine though. You’d just want to make sure you have a C02 monitor outside of the room so you can check C02 levels to make sure they don’t exceed 2000 ppm because if it exceeds 2000 ppm and you go in the room closing the door behind you to work with the plants it can be harmful you are exposed too long.

2000 ppm c02 can cause drowsiness and sleepiness, head aches, insomnia, nausea, and other issues. It doesn’t exceed work place exposure limits but can be dangerous if you fall asleep and don’t get out of the room. It has potential long term and short term effects as well.

5000 ppm is the maximum work place exposure limit.

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Wow! I did not know that about the CO2 buildup! I just want to do what is going to be most beneficial to my plants and hopefully add as few new electronic devices as I have to. My online fan has a probe for temp and humidity to kick it on and off, so that should help tremendously. I’m going to just suck it up and order one of the S series fans and charcoal canisters and be done with it. Can’t wait to have you guys some pictures soon!


@Rigs50 those ac infinity fans with built in controllers are great.

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Yep I have the ac infinity t4 don’t know what I’ll do with out it makes things simple and easy

Ok, so now I’ve got my tent together, got the 6” smart fan pushing the hot air out the top, and at the bottom I have one of the AC infinity 6” s series fan pulling fresh air in. I plan to maintain a negative pressure in the tent, but wouldn’t I want to maintain a steady exchange of air in the tent? This smart fan turns completely off when settings are right and my tent might never go above 80. I run the small fans inside any time the light is on, and then rely on the inline fans to maintain most of the airflow while the lights and fans are off. I want to definitely save on electricity but I also want to make sure these plants have proper air. If the smart fan turns off and my intake fan (not a smart fan) stays on, it will change the tent from negative pressure to positive. Will this hurt anything?

I’m building a DIY CO2 bucket later today to give that a try, and I also need to raise my humidity (it’s only 35%).

(I took pictures but I guess the files are too large to share)

What IS THE SIZE OF YOUR TENT…raise Rh - add open buckets / pails of water…