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fan+scrubber question

gnaut

gnaut

Member
ahoy! moving to a new place, more room and options to build a cab so ahead I go.

Looking to get some hands-on opinions about various fans makes and how they've applied to other growers uses.

I'm looking for a few specific fans, a 20 CFM fan to exhaust my flowering chamber which is 2x4x6, and at least a 63CFM fan to pull air over a 600w hps cooltube.

at around 20CFM, that is exchanging air every two to three minutes. Which i believe is correct, but i would like to place this fan on a scrubber, any fan/scrubber suggestions that won't turn my box into a wind tunnel?
 
FreezerBoy

FreezerBoy

Was blind but now IC Puckbunny in Training
Veteran
I think you're begging for trouble. You'll want to add a "0" on the CFMs and then double it or take a "0" off the lamps wattage. A 600's flowers are going to stink to high heaven. A 20 cfm fan, most likely axial, will choke on any filter big enough for the job.

For your edification and reading pleasure Ventilation 101
 
H

Hydrolized

Member
I agree with Freezer. 63 CFM isn't going to cool a 600...and after you add the static pressure of the ducting going to and from your light, it will be a lot less than 63 CFM...same with your 20CFM fan....try and put that on a CF and you will probably get less than 5CFM.

I would buy a 6" inline fan and pull through a CF, then through the light, then out. Takes care of light cooling and room venting at the same time. will run you about $300, but you won't be begging for trouble like FreezerBoy rightly said.
 
H

Hydro-Soil

Active member
Veteran
a Stanley fan will hook up to 6" ducting and work to cool that space... it's approximately 230cfm. There's a thread in the Link O' Rama on modding Stanley fans. :D

They hook up to "Organic Air" 6" SINGLE-PASS filters just fine and I used one for a year with my 1000w hps. No problems. :D

Stay Safe! :blowbubbles:
 
BasementBreeder

BasementBreeder

Member
The real issue is that you're using too large of a light. It's much more practical to use a 250 or 400w bulb for a 2x4 floor area. 600w is way overkill, not to mention the obvious heating issues.
 
gnaut

gnaut

Member
Sorry.. some late night reading = late night mistakes, too. I'll be running a 6inch Axial fan rated between 150-200 CFM over my lights. The ducting will be straight through from tube to light to fan. I'll also be running a blower/scrubber combo to ventilate the plants grow area. With my understanding, with aiming for 3-5mpAc, I will only need around 12 CFM through the scrubber..?

i've done quite a bit of reading over the past year, and really, the only thing i'm fuzzy on is ventilation requirements.
 
F

fungzyme

Active member
Read up on static pressure - you're going to need a fan with some power behind it to pull or push air through a conventional scrubber. Those tiny CFM numbers you're coming up with don't even correspond to any available real-world fans. The simplest way (IMO) is to get more fan than you need and dial it back (if necessary) with an inexpensive speed controller. Helps with the noise, too. If that 6 inch fan you mention is a duct booster fan (?) it also can't deal with any static pressure, so even the bulb in the air path is going to going to drop its CFM some. As long as it's a short straight run you might be okay, I don't know. I'd never personally plan on cooling a 600W bulb with that little fan, unless my grow area was a lot cooler than my house temps, I guess.

Edit: and by 'more fan than you need I'm talking about a good (centrifugal or squirrel cage) fan, not a duct booster type.
 
gnaut

gnaut

Member
I understand what fans do what and why I need it. but, what I'm asking is my CFM after the scrubber needs to be 12cfm, not the fans rating. the fan at 200 cfm to cool the light is for a 10 degree change
 
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