vents

i heard that its good to have a little bit more exhaust then intake air. but i also heard its better to have more intake than exhaust. any opinions? i have a 250 cfm and a 273. so i was just wondering which you guys thought would work better where. thanks

hi tpe,
if you have more vent than intake, then you will have a slight vacume inside your room. this is good because (this is the way i'm set up anyway) when the extraction fan is running there will be no smell around the grow room because it will all get sucked back into the room. it also means your fan will be working a little harder.

well that makes sense. do you have the vent and intake on the same side? or is your fan strong enough to bring it in from the other side?

tpemiles said:

well that makes sense. do you have the vent and intake on the same side? or is your fan strong enough to bring it in from the other side?

Click to expand...

I have ducting connectiong everything where i need it, but it is set up to pull the intake air across the room to my carbon filter. My fan (6inch Vortex) pulls air through the carbon filter, through my light, through the fan then outside.

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oh i never thought of that. through a carbon filter through the light. so wait, is it light --> fan --> carbon filter --> outside? how many plants do you got going ?

carbon filter==>light==>fan==>outside

the fan is pulling air through the filter, then the light, then ..itself.. to the outside.
But you could put the fan on either side of the light i guess.

I have 5 pretty good size plants going under 1000w hps.

ohh i get it. thanks for the input man, you've given me some things to think about lol

alright so i got another question. do you think i need a cooltube and exhaust for a 400w hps/mh setup in a 3x3x6 growbox with those 273 and 250 fans i got?

tough to say... you kindof just need to road test it to see. you should get a thermometer that records the hi and lo temps and let the setup run for a day to see what kind of temps are happening in there.

cooltubes look nice, but there's a lot of diff. options for vented hoods.

I don't know about your fans, but your most likely gonna need to exhaust the heat somehow.

you wont regret having a cool tube. if you can fit/afford one, do so.

yeah its just that the cooltube is one of the cheapest vented lights at htgsupply. i guess my question was do i need another 273 exhaust if i got the cooltube?

I just run a 170 cfm through my light which keeps it cool. as far as smell goes I have a 6'' vortex fan on top of a 6'' 2 ft long PHAT filter. there is vitually no smell, and the inline 6'' fan brings fresh air in. So I guess its all preference really and what works for you.

a properly setup cool tube pulls its air from outside the grow environment, so, the correct answer is: yes you need a separate intake/exhaust system for the grow.

however, as you can tell from the other replies in this thread, you can use the single intake/exhaust if you just put the lights in the middle of that chain... the point to ventilation is not just cooling but also air exchanging.

so you got no exhaust going out besides through the light?

alright i get it now. i'm going to have a 250cfm inline fan taking off the heat from the cooltube. then a 273 squirrel fan exhaust and 250 intake system. the 273 was $20 so i had to get it. just got to figure out how to get the carbon filter through the box shape of the squirrel fan. but thank you all for your help! i finally got this ventilation thing figured out.

i have no HID's going right now... when i had them in the past they were cool tubed and when i have them in the near future they will be cool tubed... with their own intake/exhaust and the fan pulling out the exhaust.

right now, i have CFL's running and have built a ghetto reflector over them with a plexiglass shield under them and i put my exhaust duct at the end of the plexi so that the air is pulled through them and out... the intake is just down in a lower corner of the grow area... a couple feet away (as far as possible).

as you can see, i am not doing it "correctly" either

i am pleased with how it works, my temps are within a 10 degree range and my chamber is only 2-5 degrees warmer than the ambient temperature outside the grow area.

what i do not like about this is it pulls dust through my lights, and if i had a really pungent crop, the heat of the bulbs would probably make the air smell more... and i think if the lights were totally closed off from the grow area with their own specific ducting things would be even cooler in my grow area... being able to change pressure in the environment will make it cooler.

also, should you decide to run cO2 enrichment, turning the exhaust off is required... if it is a single cooling system, the temps might sky rocket as the heat from the lights is not removed.

this is all just conceptual babble though... a single exhaust does work... it just isnt best

sweet. thanks a lot bfq. i appreciate it

yeah... if ever decide to run co2, or change my setup much, then I'll prolly have to get another fan... but, works good for now.

yeah co2 is a little too much for me right now. thanks for your help man.