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Cooler grow tent?

loving_weed

New member
Hello to all, I have a grow tent that is 7x7x7 and I face problems with temperatures. Let me begin by presenting my setup: I have 4x600w HPS in cooltubes, two of them in horizontal cooltubes and 2 of them in vertical cooltubes. The 2 HPS in the horizontal cooltubes are cooled by a 400 CFM exhaust fan. I can touch the glass without getting burned, after a while it feels a little hot to my hand, but nothing dramatical. The vertical cooltubes are cooled by 2 separate fans. One cooltube is cooled by a 150 CFM fan bringing air from outside (temperature of air from outside being 55F). The other cooltube is cooled by a 400 CFM fan, bringing air from the inside of the room (my bedroom) where the tent is located. That air is about 75F. Those cooltubes are a bit hotter, but I can also touch their glass, although it feels a little hot right from the beginning. And now let me move on the exhaust of the grow tent. I have 4 exhaust fans for this job. One fan at 400 CFM hooked with a carbon filter, 3 exhaust fans at 200 CFM each, also hooked with carbon filters. So, that give about 800 CFM in total of exhaust if we abduct the amount of CFMs lost from carbon filters and ducting. For passive intake, I bring air through my window (I have opened it a bit) and I have 6x5 inch ducts (2 for each 5 inch exhaust fan) and 2 6 inch ducts (for the 1 6 inch exhaust fan I have got). Despite the air I am bringing from outside is 55 F (I put the thermometer inside of one of the ducts to check), when I put the the thermometer in the middle of the grow tent, it reaches 80-82 F. A thought that comes to my mind is that the direction of air coming from my passive intakes is not in the diagonal way it is supposed to be considering the exhausts. You can see what i mean in the miserable pics i made with MS Paint. Do you have any ideas that could help in my case and see the desirable 75 F reading in my thermometer? Its still winter here, I cannot imagine how it will be in end of March, when I will be about to finish this grow. Thank you! http://postimg.org/image/hk1livuvh/ http://postimg.org/image/bsuni2ynr/
 

loving_weed

New member
Hello to all, I have a grow tent that is 7x7x7 and I face problems with temperatures. Let me begin by presenting my setup:

I have 4x600w HPS in cooltubes, two of them in horizontal cooltubes and 2 of them in vertical cooltubes. The 2 HPS in the horizontal cooltubes are cooled by a 400 CFM exhaust fan. I can touch the glass without getting burned, after a while it feels a little hot to my hand, but nothing dramatical. The vertical cooltubes are cooled by 2 separate fans. One cooltube is cooled by a 150 CFM fan bringing air from outside (temperature of air from outside being 55F). The other cooltube is cooled by a 400 CFM fan, bringing air from the inside of the room (my bedroom) where the tent is located. That air is about 75F. Those cooltubes are a bit hotter, but I can also touch their glass, although it feels a little hot right from the beginning.

And now let me move on the exhaust of the grow tent. I have 4 exhaust fans for this job. One fan at 400 CFM hooked with a carbon filter, 3 exhaust fans at 200 CFM each, also hooked with carbon filters. So, that give about 800 CFM in total of exhaust if we abduct the amount of CFMs lost from carbon filters and ducting. For passive intake, I bring air through my window (I have opened it a bit) and I have 6x5 inch ducts (2 for each 5 inch exhaust fan) and 2 6 inch ducts (for the 1 6 inch exhaust fan I have got). Despite the air I am bringing from outside is 55 F (I put the thermometer inside of one of the ducts to check), when I put the the thermometer in the middle of the grow tent, it reaches 80-82 F.

A thought that comes to my mind is that the direction of air coming from my passive intakes is not in the diagonal way it is supposed to be considering the exhausts. You can see what i mean in the miserable pics i made with MS Paint.

Do you have any ideas that could help in my case and see the desirable 75 F reading in my thermometer? Its still winter here, I cannot imagine how it will be in end of March, when I will be about to finish this grow. Thank you! http://postimg.org/image/hk1livuvh/ http://postimg.org/image/bsuni2ynr/

I edited the post alone, hope its ok now. Sorry for the many posts in the same thread.
 

Snow Crash

Active member
Veteran
How many circulation fans are you working with?

Your ventilation configuration is kind of boggling. With your grow tent at <400cuft you should have ample exhaust. I would try taking one of your 200cfm exhaust fans and using it as an intake fan instead. It will reduce the negative pressure in the tent without sacrificing it completely.

Getting the room the tent is in from 75 to 72 would be helpful too I imagine. And where you exhaust the heat from the tent might be a contributing factor. Are you using insulated ducting? A lot of heat can be transmitted back to the room through simple metallic duct.
 

loving_weed

New member
Issues were solved making these alterations:

1)Used the 3x450 cfm ventilation fans for exhaust. With as straight ducting as possible and a diy silencer for each of them to compensate for less ducting used. Helped a LOT with noise.

2)Used the 3x200 cfm ventilation fans and booster fan at 150 cfm for active intake.

3) Put all the bulbs vertically, in their cooltubes. Each cooltube has got a honeywell circulation fan under it at the lowest setting to gently push hot air up.

For now, i am using 3x600w, temps are sitting at 73-75 F. Gonna put the 4th bulb and check it out. If temps exceed 80 F, i will stay with 3x600w.

Better to have the right conditions with less light than more light with wrong conditions for the babies.
 
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