Ventilation Question. Pahlease Help =)

So here's the idea.

2x Comp fans for passive intake.

and the exhaust system is going to go something like this(at least it works in my head)

Hydrohut Charcoal Filter Elf (150-265cfm range).
-> ducting
Hydrofarm Cooltube.
->ducting(maybe?)
S&P inline fan TD-150(218-298cfm range)
->ducting->out of cab.

My question is whether or not it's going to work in a box running a CMH bulb w/ the dimensions of 2'dx4'hx4'w. I mentioned the use of a CMH because they run a bit cooler.

crfman88 said:

So here's the idea.

2x Comp fans for passive intake.

and the exhaust system is going to go something like this(at least it works in my head)

Hydrohut Charcoal Filter Elf (150-265cfm range).
-> ducting
Hydrofarm Cooltube.
->ducting(maybe?)
S&P inline fan TD-150(218-298cfm range)
->ducting->out of cab.

My question is whether or not it's going to work in a box running a CMH bulb w/ the dimensions of 2'dx4'hx4'w. I mentioned the use of a CMH because they run a bit cooler.

Click to expand...

that sounds like it would work in keeping the temps at around 4-8 degrees above the other ambient temps.

the only thing to remember is that if the inline fan is rated higher than the filter, than it will cause the filter to not do it's job correctly. you should go with the Goblin just to be safe. you'll have a little bit more, but to keep the air in the tent cool while pulling that air into the hood to cool the lamp, limit filter over load for odors you're filters CFM should be really close to the max CFM for the fan (though it will drop a bit with bends in the ducting, resistance created by the hood and tent..etc..).
It also depends on how quick you move the air out (duct runs) and if the grow area is insulated (keep's the heat in or radiates out of the walls).

msgmehere1 said:

that sounds like it would work in keeping the temps at around 4-8 degrees above the other ambient temps.

the only thing to remember is that if the inline fan is rated higher than the filter, than it will cause the filter to not do it's job correctly. you should go with the Goblin just to be safe. you'll have a little bit more, but to keep the air in the tent cool while pulling that air into the hood to cool the lamp, limit filter over load for odors you're filters CFM should be really close to the max CFM for the fan (though it will drop a bit with bends in the ducting, resistance created by the hood and tent..etc..).
It also depends on how quick you move the air out (duct runs) and if the grow area is insulated (keep's the heat in or radiates out of the walls).

Click to expand...

its really cold in the room in which I imagine this all would go.
and i guess i have a few more questions...

if i set the S&P at the low speed it would still be well within the cfm range and also by going with the smaller filter i can save a little bit of space.

also, would +30 cfm's really be a huge difference? =O =)

thanks.

30 cfms will in my opinion be a bit of a diff. I would get a fan from lowes.... 500 cfm is like 35 dollars and use that instead. I would however (after reading your post) make sure that the scrubber is on the INTAKE end of the fan. I answered three other people between yesterday and today that want to put the scrubber on the positive side (pushing side) of the fan. You will benefit from having the scrubber on the (negative) intake side of the fan. Your grow area is fairly small but as someone else mentioned bends in the ducting, and just general resistance of air will slow teh air movement down. Go a little larger and you will be much happier.
Sorry for the misspellings.... last puff did me in... lol...

you should be fine. just do a few temp reading before you buy this stuff. what ever the hight and low temps are can help with determining the fan. if you can exchange that air at about 200-250 cfm than you may see temps with HID lights (400/600) that range from 3-25 degree differences from external ambient temps (not exact but a guestimate based on experience). By the way, what light(s) are you going to run? going with a vented hood can aid in keeping within your cfm and keeping the temps down. Also you will have to deal with humidity levels, another factor to consider. hight for veg, low for flower.

Just remember that centrifugal fan's are better for your setup. axil based fans will crap out or the cfm will drop drastically the second you hook it up to a hood, tent and even more with the filter. You can find 4" centrifugal fan fans for around $70-150.

but if your going with CFL's or LED's, just go with what ever you want, since your heat won't be much, but more fresh air the better.