1st grow, I'm using botanicare readygro coco mix

get a pic of the dryer in relation to the box

I want to use an active air intake.
I'll use 4 inch bends to eliminate light photons.
I'll put the 4 " circular fan in the middle of the bends somewhere closer to the floor of my cabinet and have a filter bag deal at the opening of my intake .

If I have a 170 cfm, 4" inline fan exhausting heat, will I still have the negative air pressure with a 4" active air intake?

This is the fan I'm thinking of using?

Here she be

The photo you posted looks like a duct booster fan, they really don't provide much pressure. About a decade ago I used one with a DIY carbon scrubber in a closet with a 150w HPS over an eighteen gallon Rubbermaid tote full of dirt. It kept the smell down, but the airflow would not support anything other than that.

That bastard was the largest plant I've ever had under that light. I couldn't even get my arms around it.

The exhaust fan is plenty big for that volume (I estimated thirty-two cubic feet) so the negative pressure will be fine for anything you use as an intake.

The big issue are the bends and the filter, those really cut down on air flow. As a rule of thumb (I know, not the best reference), roughly half of what your exhaust fan is pulling is what your intake should be pushing.

Thanks I appreciate the rule of thumb. All those little tips really help.
So this booster fan doesn't provide much pressure which is awesome.

Let's say I use two bends.
I can mount the booster flush to the floor then immediately put a bend after the booster intake and one more bend after the first bend, topped with maybe a black filter screen deal.
That should eliminate a lot of light and with only 2 bends I wouldn't sacrifice flow, like I would with 4-5 bends.

If a little light come through all that it won't really make that big of a diff.??

Or...
Are you trying to say that a phresh carbon filter/ fan set up to intake as well as exhaust the room..
I have a legit scrubber that will scrub the smell, do i really need that muched forced air coming into room.
Or would that booster provide enough exchange, with the set up in my previous post?

The intake fan is there to take the strain off the exhaust fan, not overpower it. That's why I say to use approximately half of the flow of the exhaust, many factors play into this so each setup will be unique.

Test your builds!

See how many bends you can get away with, I'd think three minumum with a prefilter, four without, possibly five if the bends are very close together.

Paint the inside of the bends black or get the black interior lined ducting.

Light photons don't bend. They travel in straight lines.

Ive never used an intake fan, it makes no sense if you want a negative pressure to clean the air. If you want to spend money on your intake buy a nice filter, not a fan.

Intake fans are more common than you think.

youd be surprised, there is no need for it. centrifugal fans pull plenty of vacuum and you arent stressing the fan a bit. If the exhaust fan works then everything is fine, I cant imagine the exhaust failing and the intake helping a bit if the exhaust dont work.

Off topic.

Intakes fans have a purpose, your personal setup may not have one but there a more that use them than you not.

I like bogs theory of kiss. Keep it simple stupid

You should look at those running multiple lights, or those running very small stealth grows.

It is far more common than your single op.

they may pull enough, but after switching from passive intake to active intake I started getting better results with fewer instances of mold. That's just my own observation every case could be different

I am trying to cool the box with the intake as well as exchange air. 1000 watt bulb adjusted to 50%, enigma thinks ill fry them with the 3×3×5 room using that 1000 watt bulb.

With the heat created when I close the box I feel it may kill the plants, I left the box open all day and I came home from work and it was 80°.

So will that booster be enough?

Larzbarz8992 said:

I am trying to cool the box with the intake as well as exchange air. 1000 watt bulb adjusted to 50%, enigma thinks ill fry them with the 3×3×5 room using that 1000 watt bulb.

With the heat created when I close the box I feel it may kill the plants, I left the box open all day and I came home from work and it was 80°.

So will that booster be enough?

Click to expand...

You can try it, I just think the 1k is overkill.

$0.02

Haha I feel you. I'm going to try it I have already spent money and had an idea and I just want to get after it.
Trial and error, we live and learn, however, living is easier when we learn through others.

Everyone that replied to my thread I thank you. It was amazing help.

I'll holler when the girls get going.