What size fans?

DejaVuDejaVu

DejaVuDejaVu

Member
Right I am going to set up a 3x3x5ft something grow tent by secret jardin which is apparently suited for a 400w light. So I am getting the 400w ballast and bulb to cover 4 plants, but what size fans will I need for sufficient air flow? I am looking at the quieter ones like Systemair or Sunleaves etc but need to figure what size I will want to get. This is my first time setting up you see. Any help at all would be appreciated. Thanks guys. :)
 
wyteberrywidow

wyteberrywidow

Global
A 4inch vortex or the likes will be more than enough to vent the room with just a passive intake or you can get a couple duct booster fans 6 or 4 inch they are cheap but can get the job done.

I use a 39x 39x 79 in tent and I use a 4inch grow bright fan with filter to vent the tent and 1 6inch duct booster connected to my cool tube to cool the light.
 
dannyboy602

dannyboy602

Well-Known Member
Measure the cubic feet inside the tent. Look at the kinds of fans you want to run. Most fans are rated by CFM. That is to say the amount of air a fan will move in one minute measured in cubic feet. If your fan can replace all the air inside the tent in a minute then it's powerful enough. You can buy noise mufflers for fans to reduce the noise if necessary.
 
DejaVuDejaVu

DejaVuDejaVu

Member
dannyboy602 said:
Measure the cubic feet inside the tent. Look at the kinds of fans you want to run. Most fans are rated by CFM. That is to say the amount of air a fan will move in one minute measured in cubic feet. If your fan can replace all the air inside the tent in a minute then it's powerful enough. You can buy noise mufflers for fans to reduce the noise if necessary.
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I am not amazing at maths haha but I'm pretty sure my tent is around 49 square feet if it is 3x3x5.5 equals 49.5 sq ft? If that is correct then how many CFM am I looking for with a 400 watt? :)
 
DejaVuDejaVu

DejaVuDejaVu

Member
wyteberrywidow said:
more like 9 square feet;)
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LMAO I was going to say 9 square ft but then I gathered I was measuring the space of the whole box :P

EDIT: You do you multiply Width x Length x Height, so if I am right it is 49.5 cubic ft all in all, so to pass the air through 3 times a minute I will need a 150CFM, 4 times is 200 CFM and 5 times a minute would be 250CFM
 
Adjorr

Adjorr

Well-Known Member
For that space and bulb you could use a 4 inch fan running at full speed and you would be fine. However if noise is a concern a 6 inch fan running at half speed will produce less noise. It also allows you to speed the fan up if you find you need more air flow to keep the temperatures you want. Its better to have more ventilation then you need that you can scale up or down based on your needs then it is to have the bare minimum, that's my opinion anyways
 
wyteberrywidow

wyteberrywidow

Global
DejaVuDejaVu said:
LMAO I was going to say 9 square ft but then I gathered I was measuring the space of the whole box :P

EDIT: You do you multiply Width x Length x Height, so if I am right it is 49.5 cubic ft all in all, so to pass the air through 3 times a minute I will need a 150CFM, 4 times is 200 CFM and 5 times a minute would be 250CFM
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L x w for square feet and l x w x h for cubic feet.
 
ZOMBIESxWEED

ZOMBIESxWEED

Active Member
I only have a 4 inch vortex I use to exhaust air when lights are off. My only fresh air intake into the tent is an AC that turns on with the lights. I'm running a 5x5x9 tent.
 
Adjorr

Adjorr

Well-Known Member
wyteberrywidow said:
am I wrong? I thought 3x3=9square feet= 1 square yard:wall:

Back to school for me then lmao.
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your right, it is. However were trying to determine cubic feet not square feet, as I don't know how many plants youd be able to fit in a 2 dimensional space :joint:
 
DejaVuDejaVu

DejaVuDejaVu

Member
Adjorr said:
I don't know how many plants youd be able to fit in a 2 dimensional space :joint:
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Haha you make me laugh guys :lol: Thanks. Got my ballast with bulb on the way they look awesome.

Another question ;)

Say I bought a quiet fan a Vortex, Sunleaves, S&P or something similar for the exhaust... Would my intake fan have to be the same? As I have a 4" fan that was going to replace the fan which is inside the 'Walk-in shower' in the bedroom. It turned out it never needed replacing, so I still have it. I don't know much about it, it just says 50v or something on the back. It doesn't have different speeds etc. Just a fan you stick in the ceiling to take out excess moisture. Would that be a sufficient inlet? Even if it is just temporary? Please excuse my lack of knowledge but I'm getting there :P

Thanks :leaf:
 
Sir.Ganga

Sir.Ganga

New Member
Forget all the math and purchase a 6 inch fan. You can always go out and buy a controller if it is too much flow but you can't increase a 4 inch that is already at max load. Cost wise very similar.
 
Arthitiseeder

Arthitiseeder

Member
L*W*H*X x= the amount of times per minute you want the room cycled. Standard would be 3 for straight exhausting and probably 2 for scrubbing. however you also need to factor in the pipe work. add 5-10 percent per cent 45 degree bend, add 10 percent if the pipe is flex coil not hard pipe. you could get away with an inline vortex fan (4 inch) and C.F pretty easy. I would likely add a duct booster fan if I lived in a hotter or more humid environment to allow me to move some air based on that. HIH
 
Adjorr

Adjorr

Well-Known Member
you don't neccasarily need an intake fan, the negative pressure created by your exhaust fan will be enough to suck air in through passive intakes, I definatly recommend the 6inch fan with a speed controller for your exhaust
 
DejaVuDejaVu

DejaVuDejaVu

Member
Ok nice one. I will take Adjorr & Sir.Ganja advice and just go for the 6" fan with controller then :)

So it would be better to let the air flow through 5 times though rather than just the 3 to help shift odour along faster (the english [ EDIT: British :P ] spelling of Odour lol, the word 'Colour' should also have a U in it ;) But it always tells me I'm spelling it wrong haha) I'd somehow feel more comfortable with 5 times a minute anyway lol.
 
DejaVuDejaVu

DejaVuDejaVu

Member
Adjorr said:
you don't neccasarily need an intake fan, the negative pressure created by your exhaust fan will be enough to suck air in through passive intakes, I definatly recommend the 6inch fan with a speed controller for your exhaust
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And I know it's kind of off the subject but I just thought I would show you what ballast and bulb I'm getting. :D

http://www.ebay.co.uk/itm/Grow-Lights-250w-400w-600w-1000w-Ballasts-Hydroponics-Lights-4-Tents-HPS-Bulbs-/230918188380?pt=UK_HomeGarden_Garden_PlantsSeedsBulbs_JN&var=&hash=item35c3cbed5c
 
Arthitiseeder

Arthitiseeder

Member
DejaVuDejaVu said:
Ok nice one. I will take Adjorr & Sir.Ganja advice and just go for the 6" fan with controller then :)

So it would be better to let the air flow through 5 times though rather than just the 3 to help shift odour along faster (the english [ EDIT: British :P ] spelling of Odour lol, the word 'Colour' should also have a U in it ;) But it always tells me I'm spelling it wrong haha) I'd somehow feel more comfortable with 5 times a minute anyway lol.
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likely yes, the only thing you want to watch is that your carbon filter matches up with how much air you move. moving too much air through too fast will negate the benefits pretty quick. I went with a can 2600 but I also have an air inlet that goes through an additional CF. so short story long, as long as your filtering matches the specs you're in like Flynn :-) HIH
 
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