Carbon filter not working?

I'm starting to have a serious problem with the smell of my plants. Let me tell you a little about my setup. I have a 3.5'x3.5'x6.5' Homebox tent in the corner of a bedroom. Inside the tent I have a 400w HPS cooltube and a 4" 170 cfm exhaust fan. I didn't have the carbon scrubber hooked up until just a week ago. I started smelling the plants when I walked into the room so I hooked it up. The air from inside the tent gets pulled through the carbon scrubber, then through the cooltube, then through the exhaust fan and out into the bedroom.

When I first started smelling the plants from just entering the bedroom I hooked up the scrubber and the smell went away, until a couple days ago. It's not too bad at the moment but the smell fills the room and smacks you in the face as soon as you open the bedroom door. I have the exhaust running 24/7 and I'm not sure what to do.

Here's the kicker, I'm still in veg!!!! I've got about a week before I start flowering so I need to take care of this problem asap.

Any suggestions?

p.s. here's my gear: Filter + Fan

do you have a passive intake, are you creating negative pressure in the grow area?

You have to examine your airflow.Even with a good filter if the air is diffusing up through the floorboards or out a closet door the filter dosnt have an oportunity to scrub the air.

Also if those fans are "free air" dumping into the filter with no tubing, there isnt enough pressure to force the air through the filter, alot of air escapes through the blades of the fan. (you will feel air pushing out inside of sucking in) Adding additional tubing to aid pressure build up might help.

You might need to seal up your growroom with some sort of vapor barrier like plastic sheeting.

yes, tent zipped up with the 3 vent flaps open. The sides of the tent suck in so there is neg pressure.

shit, that sucks! what strain are you growing?

speedhabit said:

You have to examine your airflow.Even with a good filter if the air is diffusing up through the floorboards or out a closet door the filter dosnt have an oportunity to scrub the air.

Also if those fans are "free air" dumping into the filter with no tubing, there isnt enough pressure to force the air through the filter, alot of air escapes through the blades of the fan. (you will feel air pushing out inside of sucking in) Adding additional tubing to aid pressure build up might help.

You might need to seal up your growroom with some sort of vapor barrier like plastic sheeting.

Click to expand...

Did you even read my post? The air is being pulled (yes with flex vent) from inside the tent through the filter, through the cooltube, and out into the bedroom. I'm using a text, the damn thing is made out of poly. Please read the entire post before replying with non sense.

gangjababy said:

shit, that sucks! what strain are you growing?

Click to expand...

HGS White Russian. Plants are about a foot tall with fan leaves bigger then my hand.

a couple of suggestions - try shaking the filter canister as sometimes the carbon needs to be distributed. try taping the filter to the fan as any leaks there cause air to bypass the filter. seal the tent as others have suggested. you;ve got a good filter so the problem is the setup

desertrat said:

a couple of suggestions - try shaking the filter canister as sometimes the carbon needs to be distributed. try taping the filter to the fan as any leaks there cause air to bypass the filter. seal the tent as others have suggested. you;ve got a good filter so the problem is the setup

Click to expand...

Sealing the tent is not an option. I'm using a passive intake and if I sealed the tent I'd have other problems. Hooking the filter directly to the fan isn't really an option because I need to cool the light. I guess I could set it up so the air goes from the tent through the cooltube, through the fan, then through the filter and into the room.

midgaar said:

Sealing the tent is not an option. I'm using a passive intake and if I sealed the tent I'd have other problems. Hooking the filter directly to the fan isn't really an option because I need to cool the light. I guess I could set it up so the air goes from the tent through the cooltube, through the fan, then through the filter and into the room.

Click to expand...

wait - i don't think i understand how you've set up the filter. is it in the tent with the ducting going from filter to fan to light to exhaust or do you have the filter in the tent with the input and output inside the tent?

also, when i suggested sealing the tent i should have made it clear that you need some gaps for air. but i see you're already running negative pressure so no worries.

desertrat said:

wait - i don't think i understand how you've set up the filter. is it in the tent with the ducting going from filter to fan to light to exhaust or do you have the filter in the tent with the input and output inside the tent?

also, when i suggested sealing the tent i should have made it clear that you need some gaps for air. but i see you're already running negative pressure so no worries.

Click to expand...

I have the filter inside the tent. The filter is ducted to the cooltube light. The cooltube is ducted to the fan. The fan is ducted out of the tent. The walls of the tent, when zipped up, suck inward suggesting a neg pressure inside the tent. The only problems I could possibly think of is a leak in the venting somewhere or the carbon filter itself isn't working. I also considered the air was moving to fast through the filter and not being cleaned properly but the fan is rated at 170cfm and with all the venting it can't be pulling air faster then half that.

I've just finished moving the filter outside the tent. I now have one end of the cooltube open with the other end connected to the exhaust fan. The exhaust is connected to the filter blowing air out into the room (insted of sucking air in as the last setup had).

Your humidity could be too high. I believe at about 60 to 70% (someone correct me if i'm wrong) humidity, the carbon becomes too moist to filter the smell.

it really sounds like you;'re on top of this, just a couple of ideas: i've heard of people pushing and pulling air thru the filters. pulling air makes more sense to me as it puts the filter in the grow area nearest the smell making leaks less critical.

did you buy your filter new? maybe your activated carbon is not so activated after all.

170 cfm is fine if you don't have significant back pressure. try running the filter without ducting in the tent. if the smell goes away then you probably need a stronger fan.

desertrat said:

it really sounds like you;'re on top of this, just a couple of ideas: i've heard of people pushing and pulling air thru the filters. pulling air makes more sense to me as it puts the filter in the grow area nearest the smell making leaks less critical.

did you buy your filter new? maybe your activated carbon is not so activated after all.

170 cfm is fine if you don't have significant back pressure. try running the filter without ducting in the tent. if the smell goes away then you probably need a stronger fan.

Click to expand...

Well I already took the filter out of the tent and made it the last step in the exhaust cycle. The air is being pushed through it now. This was two hours ago and the smell has gone away. As nice little bonus my temps dropped like 5 degrees. From 81 to 75 degrees. Now I don't know if this is because of the change or the fact the sun has gone down but I'm sure it at least 2 degrees lower then what it normally is at this time.

I'll snap a picture of the venting for you.

The carbon filter Should be pulled through, this way your not building up pressure of odor inside the filter And fan.

Give your filter a good shake, hook up the fan DIRECTLY to the filter Pulling!! This is the most important thing you should do.

You said you had filter->ducting->cooltube->ducting->fan thats 3 places where you lost major pressure, and possible suck in odor after the filter.

If the fan is directly pulling through the filter, the filter, the fan, your ducting and cooltube is ALL gettinng Pressurized with Clean air, that eliminates connections where odor can leak in. Then you should duct tape everything!!! all the connections, the problem is not the tent, its just your setup.

Filter->Fan(pulling) -> ducting -> Cooltube -> Exhaust
Everything after the filter and fan is clean air, no places for odor to contaminate.

If you set it up right you will have no problems.

Hope this helps.

Here's a picture of the old setup:




Here's two of the new setup: *Note there's nothing attached to the other side of the cooltube*





Bonus pictures of my babies. I just transplanted them to the 3 gallon pots about an hour ago. The small ones are a week or two behind the bigger ones.





Anyway, I hope this solves the problem otherwise I don't know what else to do besides buying a bigger filter.

Nice pics, looks good but read my post just before this one, Trust me a quick fix is nice but you want the proper solution

BCtrippin said:

The carbon filter Should be pulled through, this way your not building up pressure of odor inside the filter And fan.

Give your filter a good shake, hook up the fan DIRECTLY to the filter Pulling!! This is the most important thing you should do.

You said you had filter->ducting->cooltube->ducting->fan thats 3 places where you lost major pressure, and possible suck in odor after the filter.

If the fan is directly pulling through the filter, the filter, the fan, your ducting and cooltube is ALL gettinng Pressurized with Clean air, that eliminates connections where odor can leak in. Then you should duct tape everything!!! all the connections, the problem is not the tent, its just your setup.

Filter->Fan(pulling) -> ducting -> Cooltube -> Exhaust
Everything after the filter and fan is clean air, no places for odor to contaminate.

If you set it up right you will have no problems.

Hope this helps.

Click to expand...

This makes a lot of sense. I've read other places it doesn't really matter if you pull or push air through the filter. Naturally I want to pull the air through it and had it setup like that but I changed it. If that doesn't fix the problem I'll be sure to try it your way before spending any more $$.

Just so I got this right, I want to pull the air through the filter and then push it through the cooltube and then out of the tent?

BCtrippin said:

Nice pics, looks good but read my post just before this one, Trust me a quick fix is nice but you want the proper solution

Click to expand...

You keep posting on me while I'm replying.

If the fan is hooked up strait to the filter, pulling air through. The fan will then be pulling odor from the outside, so its clean air filling up the inside of the filter, then its clean air going through your ducting and cooltube, that will eliminate any odor leaks.

If you push through the filter, your filling up all your ducting and your cooltube with odor and even your fan is being filled with pressurized stank air, which can lead to more leaks.

I always prefer to pull, that way all the exhaust air running through my ducting is pressurized and clean so it cant be contaminated on its way out.