Using carbon filters

I'm trying to find a (somewhat) definitive answer about the air pathways when an air-cooled hood and a carbon filter are both used. I thought, blow the fan over the light, connect the carbon air filter on the exhaust. But if I'm bringing air in from outside the room to cool the lights, it doesn't really need to be scrubbed. Not only that, but I would have no ventilation in the room that way. So do I have two exhausts: one from the lights, and one from the scrubbed air? I'm confused, and can't find anything that seems to address this particular setup. Thank you in advance.

Hook the carbon filter up with your venting to your cool tube light and any other subsequent lights with venting in between.

Run the end of venting up and away someplace preferably like an attic, install the centrifugal fan in the attic. Say ... mounted to roof trusses. The venting after the centrifugal fan, run that remaining venting into a vent cap (roof) and exhaust the heat out of that vent to outside. Staple the venting to the wood pointing out to the hole where vent cap is.

The room just needs an inlet or two to get fresh air.

Use aluminum venting DO NOT use plastic like a dryer uses. The smell will soak into the plastic and bypass the scrubber !

The way I have mine set up is the the fan is pulling the air through the filter then thelight and then pushes the out of my tent to out side

This is not my set up but it's very similar, my fan is complete out of my tent and hooked to an old dryer vent pumping everything outside

^ this, some people will tell you to have the fan pushing into the light so it doesn't get hot, which is bullshit, these fans are designed to work with exhaust systems, which get hotter than your lights ever get.
suck it in through the filter, through the light, then the fan, then the exhaust, only thing i would do different in the pic above is to have the filter suspended higher than the light, you want it to suck hot air out of the tent, and the hot air is at the top of the tent

Yeah have that filter up as high as you can get it, hot air rises

Generally the scrubber should be level with the lights or higher depending on ceiling height.

The heat should be exhausted upwards after and out for best efficiency.

The above suggestion is not ideal. Having the fan PULLING from so far back in the system could pull in air from your room through leaks (even pinhole sized) in the reflector and venting. You could be pulling dirty air in that would bypass the filter...

General consensus seems to be to PULL through the filter then PUSH through the reflector and rest of the system. This means mounting the fan directly onto the carbon filter inside the room. The alternative is to pull through the reflector and venting (leaving one end of the reflector open) and push through the filter.

FYI this comes up a lot in grow room design you'll find a lot of info there.

i don't see this as being that important, unless you're really bad at using clamps and duct tape. a couple of pinhole sized leaks aren't going to defeat the purpose of having a filter.
for a lot of people mounting the fan inside the tent is either impractical or just plain impossible. a lot of people here aren't big time with 100s of plants, they grow 2 or 3 or 5 at a time, in a small tent, no room to put a fan in it if they wanted to, barely room for the filter.
mount your fan however you see fit. if the threat of a couple of pinhole sized leaks seems that important to you, do what ya gotta do

this is all very Exhausting,,, lol

don't make me come over there...
i'll turn this website around and no trip to grandmas...

Roger A. Shrubber said:

i don't see this as being that important, unless you're really bad at using clamps and duct tape. a couple of pinhole sized leaks aren't going to defeat the purpose of having a filter.
for a lot of people mounting the fan inside the tent is either impractical or just plain impossible. a lot of people here aren't big time with 100s of plants, they grow 2 or 3 or 5 at a time, in a small tent, no room to put a fan in it if they wanted to, barely room for the filter.
mount your fan however you see fit. if the threat of a couple of pinhole sized leaks seems that important to you, do what ya gotta do

Click to expand...

You aren't wrong. But having recently switched genetics and finding that I'm now exhausting air that smells like decaying human feces into my neighbours backyard I figured I'd mention it. My reflector is leaking and it only become obvious with new genetics. Moving the fan fixed it.

glad ya got it fixed. keep in mind, it could also be the age of your filter, they last about two years with proper maintenance. they want to draw from the top end where the suction is strongest, some people wrap saran wrap around the top 1/3 to 1/2 of their filter to make it draw from the bottom, then after 6 months or a year, they take it off so it can draw from the other end. if you feel handy, you can also grind the rivets off that hold the end cap on, and either pour the carbon out, bake it, and use it again, or replace it with fresh carbon, getting another year out of your filter.

Roger A. Shrubber said:

glad ya got it fixed. keep in mind, it could also be the age of your filter, they last about two years with proper maintenance. they want to draw from the top end where the suction is strongest, some people wrap saran wrap around the top 1/3 to 1/2 of their filter to make it draw from the bottom, then after 6 months or a year, they take it off so it can draw from the other end. if you feel handy, you can also grind the rivets off that hold the end cap on, and either pour the carbon out, bake it, and use it again, or replace it with fresh carbon, getting another year out of your filter.

Click to expand...

To regenerate carbon you need a bit more than the oven will produce, that's what they make autoclave's to do it, just an FYI. Also I just bought 25lbs for $20 on Amazon, I'll test it and see if it's any good .

I have a 10 x 11 room so it needs some air movement and exhaust. I went with an 8" fan right at the carbon filter. I didn't have time to get it mounted to the ceiling before I had to get these girls flowering. So for now it's on the floor and theres a BIG fan mixing up the air so I don't get a hot zone.

But I considered that from the floor, it's going to have to make a 90 degree bend, make it's way through 2 lights and a couple of 45 degree bends. Each of those disruptions to the air flow slow down the whole flow rate. So I added a second 8" fan near the first light. I was going to put it toward the end, sort of as a final push outside - but space limitations made it impractical.

After this batch is done, I'll reconfigure it and hang the filter from the floor joists above the drop ceiling.

I attached a 6" vent to some wood at a basement window and vent it directly outside. I have a filter at the end just so nothing could make it's way back in.