Small Box Ventilation Question

hey guys, had a bit of a ventilation question for ya.

my space is about 6 cubic feet in area, and i have about 400w of CFL light...I had trouble bringing the temps down with just my (2) 120mm computer fans, (1 intake, 1 pushing out) so I bought a 250cfm fan, however...the temps still seem to be climbing a bit to high, (85's) with no ladies in there. I figured this fan would be pushing enough air for proper ventilation. However, Any ideas on how to increase ventilation and bring down some temps?

Try makin the intake bigger then the exhaust

put sum cups of ice in there everyday

i'll give it a shot man thnx for the heads up. I figured with 2 outwards blowing fans would be enough to keep the hot air down, but I'm gonna try and drill some holes in the bottom of the backpiece to increase fresh air. I've heard of that ice trick, does it really work well?

milleniumgrenade said:

i'll give it a shot man thnx for the heads up. I figured with 2 outwards blowing fans would be enough to keep the hot air down, but I'm gonna try and drill some holes in the bottom of the backpiece to increase fresh air. I've heard of that ice trick, does it really work well?

Click to expand...

ice trick is a pain in the ass, did not work for me

I'm not sure what type of CFL's you're using. Any way to move the ballast outside of the box?

TechnoMage said:

I'm not sure what type of CFL's you're using. Any way to move the ballast outside of the box?

Click to expand...

nah not really man they are the standard screw in, i had some plug in's but the ballast was too much of a headache. there is quite a bit of heat comin off the CFLS. I cut 4 holes in the mid-bottom section and gonna have a big fan blowing at the back of the box, hopefully this will increase airflow.

Yeah, I ran into the same problem. I had over 400 watts of CFL's in my flower cab. I got rid of the CFL's and put in a 250w cooltube. Yield went up and temps dropped.

milleniumgrenade said:

nah not really man they are the standard screw in, i had some plug in's but the ballast was too much of a headache. there is quite a bit of heat comin off the CFLS. I cut 4 holes in the mid-bottom section and gonna have a big fan blowing at the back of the box, hopefully this will increase airflow.

Click to expand...

Might not be a matter of more fans or higher cfm, might be a matter of better fans, or rather more appropriate fans, like a centrifugal.

TechnoMage said:

Yeah, I ran into the same problem. I had over 400 watts of CFL's in my flower cab. I got rid of the CFL's and put in a 250w cooltube. Yield went up and temps dropped.

Click to expand...

yea dude with a smaller space like mine, (dresser 3' x 2' x 1.5') the CFL's heat the box up rather quickly. Hopefully I'll be able to push past in with this first set-up and invest in a cool-tube or air-cooled hps for the next grow (as i'm kinda nearing the end of my improvement funds for this grow)

You know of any good HPS set-ups out there? There seem to be sooooo many brands, I'm looking for probably a 250w guy (just doin some research so I can make a smart investment when the time comes)

TechnoMage said:

Yeah, I ran into the same problem. I had over 400 watts of CFL's in my flower cab. I got rid of the CFL's and put in a 250w cooltube. Yield went up and temps dropped.

Click to expand...

also, how was your yield with CFLS? You said you had about 400w? I got about 300w and with the small space it seems like it puts off quite a bit of light.

And how much would you say the temps dropped w/ the cooltube?

milleniumgrenade said:

yea dude with a smaller space like mine, (dresser 3' x 2' x 1.5') the CFL's heat the box up rather quickly. Hopefully I'll be able to push past in with this first set-up and invest in a cool-tube or air-cooled hps for the next grow (as i'm kinda nearing the end of my improvement funds for this grow)

You know of any good HPS set-ups out there? There seem to be sooooo many brands, I'm looking for probably a 250w guy (just doin some research so I can make a smart investment when the time comes)

Click to expand...

I got mine from BGHydro.com. Their Cool Breeze 6" with a Galaxy digital ballast. Only ones I've ever owned so I can really compare to others.

milleniumgrenade said:

also, how was your yield with CFLS? You said you had about 400w? I got about 300w and with the small space it seems like it puts off quite a bit of light.

And how much would you say the temps dropped w/ the cooltube?

Click to expand...

I got about 3oz dry using just CFL's. That was with three 55w T5's above the plants and eight 32w T8's as side lighting. First photo below of what it used to look like might make it easier to understand. All together I was running 421w of cfls. My temps were running about 15 degrees above room temp.

When I switched to the 250w cooltube I ripped out all the side lighting. Second photo shows what my cab looks like now.

My first harvest after switching to the 250w, I got 6oz dry. Temps now run 5 degrees above room temp.

The big difference is that the bulb is cooled but more important, the ballast for the HPS sits outside the cab. Having 5 ballast for the CFL's in the cab added a lot of heat.

damn dude, the reflectivity of the box hurts my eyes through the computer screen ha, i bet your ladies are lovin it.

right now i have 2 (105w) daylight, and 4 (47w) 2700k bulbs, under a home-made reflector. QUIIIIIIITE a bit of heat coming outta it. Hopefully I can pull enough out of this harvest so I can invest in a hps for this next grow. And thanks for the tip about the ballast located outside, I have just the spot.

It's crazy how much your yield increased when you switched, damn do I wish I had saved a bit of cash for that.

i have set up janky "cool tubes" by using a sheet of plexi glass just below he bulbs. If you leave a gap and have outtake at the top youll keep most of that heat above the plexi glass. just an idea

past times said:

i have set up janky "cool tubes" by using a sheet of plexi glass just below he bulbs. If you leave a gap and have outtake at the top youll keep most of that heat above the plexi glass. just an idea

Click to expand...

I'm in the same boat as the OP. I've been trying to get a piece of glass to do exactly what you recommend. I have a feeling my temps will go down quit a bit once I do that. I have 2 exhausts right above my 12 CFLs.

Do what I did. I took a bunch of the CFL's that had been in the flower cab and started using them in my two new smaller cabs for moms/clones/seedlings/vegging.

Being able to clone and not having to worry about sexing made a huge difference for me. The whole reason I'm doing another seed grow now is that I have enough weed stored up to last me a year. My entire seed grow could end up being males and I'd be good because I still have my mother and I could just start up another batch of clones.

milleniumgrenade said:

damn dude, the reflectivity of the box hurts my eyes through the computer screen ha, i bet your ladies are lovin it.

right now i have 2 (105w) daylight, and 4 (47w) 2700k bulbs, under a home-made reflector. QUIIIIIIITE a bit of heat coming outta it. Hopefully I can pull enough out of this harvest so I can invest in a hps for this next grow. And thanks for the tip about the ballast located outside, I have just the spot.

It's crazy how much your yield increased when you switched, damn do I wish I had saved a bit of cash for that.

Click to expand...

dude oh man, talk about get on your level. You read my mind brotha.

I plan on making it past this first one, and using the CFL's (which are rigged up rather decent in my opinion) and use 'em in my veg cab. (mother and clones) I've been readin on those cooltubes, and they don't have 'em at that site, but it 250w certainly seems like the way to go, with the ballast outside the box. I guess at this point, I just need to find a reliable place to buy a cooltube online. How's the spread of light with them just seems kinda cylindrical...?

get some dry ice, and hang it in a bucket at the top of your box...the dry ice will add co2 allowing you to run your box a little hotter as well as cooling off your box...

Well the one I got isn't strictly a cool tube as you can see from the pictures. The big thing is air cooling to keep the heat down. It also let's be keep my light very close to the top of the plants.

milleniumgrenade said:

dude oh man, talk about get on your level. You read my mind brotha.

I plan on making it past this first one, and using the CFL's (which are rigged up rather decent in my opinion) and use 'em in my veg cab. (mother and clones) I've been readin on those cooltubes, and they don't have 'em at that site, but it 250w certainly seems like the way to go, with the ballast outside the box. I guess at this point, I just need to find a reliable place to buy a cooltube online. How's the spread of light with them just seems kinda cylindrical...?

Click to expand...

TechnoMage said:

Well the one I got isn't strictly a cool tube as you can see from the pictures. The big thing is air cooling to keep the heat down. It also let's be keep my light very close to the top of the plants.

Click to expand...

oh my bad i didn't see that, thought it was home-made. I didn't know you could buy them with the reflector attached.

air-cooling my light is the next step for sure.