Help venting my 4x4 tent with 4in inline fan exhaust

[Kjc99]

Hey guys im finishing up my first grow and need some major help.... I had a 4x4 grow tent with a 400w hps bulb and everything was running great... But today I upgraded my bulb to a 600w and it's getting frickin hot... I tried to rig my reflector wing and I put my exhaust right near the bulb and I have one fan blowing in there... I have 2 passive flaps opened... I'm pretty broke or else I'd upgrade to a 6 or 8 inch exhaust but can't at the moment... Just looking for advice on how to keep it cooler without having to purchase anything.... I originally had my exhaust at the top of the tent... But you can see from the pictures I'm trying to suck air from the bulb what will keep it cooler... Temps in top corner of tent are 74° but at plant level I went up to 87° with the 400w it was 79...heres some pictures of my setup any advice greatly appreciated The 4in exhaust will eventually have to be upgraded but what would help another fan blowing at the bulb? Open another passive vent? Move exhaust back to the top? Also in pics the white thing hanging near plants is my thermometer is this an appropriate place to put it... Fan is 159cfm with no carbon filter

 

[Beezcheeze]

Try removing the duct between the 4" fan and the light. Also move that ocellating fan so it's blowing straight across the canopy, not blowing the heat down. put a box fan in front of the intake hole on full blast. Close ac vents around the house more and open the one in this room more. But yea I had the same problem with a 4" fan had to get a 6. Kinda wish I got an 8" for my 4x4 tent.

 

[Beezcheeze]

But honesty could get away with it if you had an air cooled hood.

 

[Kjc99]

But honesty could get away with it if you had an air cooled hood.

So have the exhaust near the top of the tent and blow air over the canopy not down at it right? No Air conditioning... I live in Alaska... So it's cold outside but hate to leave the window open all day... Stupid guy at the hydro store said I'd be OK... Should of asked here first... Use a box fan to blow air into one of the lower mesh passive intakes? That's what you meant right?

 

[Kjc99]

Ya air cooled would have been a good idea.... Do you think rigging that exhaust to the reflector is even doing anything?... Definitely go with a 6 or 8 next upgrade I think the ports on this new tent go up to 10 inches.... I bought everything for a 2.7x2.7x6 foot tent and wanted to max out my ballast with this new 4x4 tent and use the 600w...i dont want to go back to 400w.... Is there a big yeild difference between 400w and 600w? And how far away usually from the tops? I know people always say to use your hand to feel the heat but what distance in general... Sorry about all the questions but your the only responder....

 

[Cobnobuler]

Thats an open bulb and thats a lot of your problem. If you can spare even 50 some bucks you can get a glass covered hood and knock down a lot of that AND you can get it a little closer.

 

[R1b3n4]

my temps in a 4x4 cupboard dropped by over 15-20 degrees when i swapped to an air cooled hood

 

[harris hawk]

View attachment 3367152 View attachment 3367153 View attachment 3367154 Hey guys im finishing up my first grow and need some major help.... I had a 4x4 grow tent with a 400w hps bulb and everything was running great... But today I upgraded my bulb to a 600w and it's getting frickin hot... I tried to rig my reflector wing and I put my exhaust right near the bulb and I have one fan blowing in there... I have 2 passive flaps opened... I'm pretty broke or else I'd upgrade to a 6 or 8 inch exhaust but can't at the moment... Just looking for advice on how to keep it cooler without having to purchase anything.... I originally had my exhaust at the top of the tent... But you can see from the pictures I'm trying to suck air from the bulb what will keep it cooler... Temps in top corner of tent are 74° but at plant level I went up to 87° with the 400w it was 79...heres some pictures of my setup any advice greatly appreciated The 4in exhaust will eventually have to be upgraded but what would help another fan blowing at the bulb? Open another passive vent? Move exhaust back to the top? Also in pics the white thing hanging near plants is my thermometer is this an appropriate place to put it... Fan is 159cfm with no carbon filter

Great set up - maybe look into a larger exhaust fan or place some smaller fans in grow area. Need to exchange air every 5 minutes or so - fans might be to small for area. Need to figure your "cfm's" there is a formula to determine that

 

[ChemPro]

A 159cfm fan is pretty small for a 4x4 600W setup. I use a 159cfm in my 2x4 tent and that is just to remove stagnant air. I have a separate $30 booster fan hooked up to my air cooled hood just for heat. The air that is used to cool the hood never makes contact with the tent. It pulls air from outside, passes it over the glass enclosed hood, and pulls it outside. Your set up is pulling air that is already warm over the light and out of the tent. It wont be effective in cooling the bulb because the air you are using to cool is already pretty warm. All the fans in the world pointed at the bulb will just redistribute heat but wont be effective in evacuating the heat. In this case your limiting factor is how much air you are able to pull out and that is effected by your 159cfm fan, which is too small for this setup. A bigger fan may help, a 400+cfm. Jury rigging your hood with a glass enclosure, and hooking up a cheap booster fan for the bulb alone will help. Placing your oscillating fan so that it points toward the bulb may force the air that is being warmed to go up into your exhaust instead of your tent. I use a 400cfm fan in my 600W 4X4 setup. Did you get a separate ballast or is your ballast/hood capable of supporting multiple wattage bulbs. If you put a 600W bulb in a 400W setup you may have an entirely new set of problems.

 

[Kjc99]

A 159cfm fan is pretty small for a 4x4 600W setup. I use a 159cfm in my 2x4 tent and that is just to remove stagnant air. I have a separate $30 booster fan hooked up to my air cooled hood just for heat. The air that is used to cool the hood never makes contact with the tent. It pulls air from outside, passes it over the glass enclosed hood, and pulls it outside. Your set up is pulling air that is already warm over the light and out of the tent. It wont be effective in cooling the bulb because the air you are using to cool is already pretty warm. All the fans in the world pointed at the bulb will just redistribute heat but wont be effective in evacuating the heat. In this case your limiting factor is how much air you are able to pull out and that is effected by your 159cfm fan, which is too small for this setup. A bigger fan may help, a 400+cfm. Jury rigging your hood with a glass enclosure, and hooking up a cheap booster fan for the bulb alone will help. Placing your oscillating fan so that it points toward the bulb may force the air that is being warmed to go up into your exhaust instead of your tent. I use a 400cfm fan in my 600W 4X4 setup. Did you get a separate ballast or is your ballast/hood capable of supporting multiple wattage bulbs. If you put a 600W bulb in a 400W setup you may have an entirely new set of problems.

Thanks for the help.... Ya I figured the fan would be pushing it in this setup... My ballast runs 400w/600w bulbs... Stupid thing is everyone always says to go bigger on the fan and put it on a speed controller... My last tent was so small that it only had 4in duct holes and I didn't want a reducer... So at the moment I'll have to deal with it and add more fans... A couple people said to move my oscillating fan so it's not blowing down.... I'll try that first and hope it helps. ... But it sounds like I need to purchase a bigger exhaust... The air in the actual tent isn't that hot... It's just hot between the bulb and canopy

 

[Aeroknow]

Either way, you should get an air-cool hood, IMO. Especially in a tent
So then you would keep your fan sucking from up high(hopefully the 4" would work), then ducted down and through the air cooled hood, and finally out the tent.
I'm not saying the 4" fan will work that way, but it might.
I'm all for bare bulbs, when I can, but air cooled hood in a tent is how I would hook it up for sure

Thanks for the help.... Ya I figured the fan would be pushing it in this setup... My ballast runs 400w/600w bulbs... Stupid thing is everyone always says to go bigger on the fan and put it on a speed controller... My last tent was so small that it only had 4in duct holes and I didn't want a reducer... So at the moment I'll have to deal with it and add more fans... A couple people said to move my oscillating fan so it's not blowing down.... I'll try that first and hope it helps. ... But it sounds like I need to purchase a bigger exhaust... The air in the actual tent isn't that hot... It's just hot between the bulb and canopy

 

[Kjc99]

Hey guys just an update.... Thanks for everyone's help... I put the fan so it's not blowing down and removed the redneck air-cooled wing reflector thing I had and it already dropped my temps down to 80° Hopefully my lights are not to far away as I'm in the first couple weeks of flower and I don't want to much stretch going on. ... What's the recommend distance for a 600w bare bulb.... I know the back of the hand heat test but I was wanting to get them as close as possible.... Definitely will be upgrading my exhaust & reflector as soon as I can come up with the money....