Getting odor through Carbonfilter only RIGHT at lights off?

[Lurking4Years]

Hey there all you Icmager's, I have a little dilemma on my hands.

I'm running a little 400 watt cab(48" by 19" by about 6 foot). I've got an S & P 150 sucking the air (not pushing) from a cooltubed 400 watt hps and can filter 33 and exhausting out of the back of the cab. When the lights are on, all you smell is sweet carbon. When the lights are off, all you can smell is carbon. BUT, right when the lights go off, I get a distinct odor of plant matter. I'm 3 weeks into flower now so its not ridiculous, and it only lingers for 20 minutes or so. Has anyone else encountered this before? Is it because of a drop of R/H or something? Anyway I can correct this? Can filter is a little less than a year old.
Also, when I took the flex duct off from the filter to the cooltube, I noticed it had a million little holes where light shown through it. I did a quick ceran(?) wrap job around it just in case some smell was passing through that, hasn't helped any. Where do you folks get that white ducting? Is white flex poly duct better than this crap aluminum I picked up from Home Depot? Sorry for so many questions!

Thanks in Advance

 

[ZENARCADE]

So what is happening when lights go off to change things? Does something in the path of the airflow change on a timer? Usually at lights off the humidity goes up which could slightly increase smell but if you have a filter I don't think you could notice. Can filters start to go down hill at around 18 months, but if they are exposed to high humidity they shit the bed even faster.

I have my cooltube ducting on its own fan separate from my main scrubber exhaust. The cooltube ducting has a damper as it leaves the room so when lights go off, cooltube fan goes off, damper closes, no pinhole leaks. My scrubber exhaust stays on 24/7 so I wrap the ducting with 4ml black sheathing plastic (paint section of your local hardwear store).
No light leaks!

 

[SGMeds]

Pulling air through the CT's & tubing will allow for trace odors to get in through each & every little hole/rip/tear/puncture/gap. No way around it unless you truly make it 'air-tight'... which is easier said than done.

If you push the the air through... get to take advantage of positive air pressure w/in the tubes & the leaks work the other way... no odors.


Also, you might want to try Thermoflo SR ducting... really it isn't very expensive & is of much higher quality than the shit out of SS & HF, which is what most stores stock. Also, if you go to HD/Lowes, you can get insulated flex ducting that will eliminate any light leaks.

GL

 

[good drown]

whats the humidity level, and what size filter? like zenacade said, they only last 18 months in normal conditions, and 1 year or less with higher humidity(like 50% or more)
i usually get 1 size bigger than i need or more, as odor can get you busted

 

[ZENARCADE]

NEVER skip on the filter, GO BIG!!!!!!

 

[Lurking4Years]

Thanks for all the quick replies folks.

ZENARCADE: Nothing changes in the path what-so-ever when the lights go out. Thats what I don't get. There is ZERO odor during lights off, and lights on. Its only for like 20 minutes that I can smell anything, right as the lights go out. I don't get it. I seem to remember this happening the last time I flowered as well, and the filter was only like 5 or 6 months old at that time. Good call on running cooltube separate from exhaust though, I was debating going that route, although thinking it would just complicate matters. I like that idea a lot though because I could size down my exhaust fan significantly.
Oh yeah, I thought I WAS going overkill on the scrubber! I had a can filter 9000 in before, and that was only rated at like 126 cfm! This can filter 33 is rated at 400cfm.

SGMeds: I only went with the pulling as opposed to pushing air because the consensus seemed to be that it was more efficient. Although the way you put it, having the leaks work in the opposite way, makes perfect sense and next run I'm thinking of switching my setup to that. That Thermoflo ducting looks nice too btw. How big would a 25' run of that be though getting it delivered, considering the fact that its pre-insulated. I'd imagine it would be in a huge box!

good drown: I feel like an ass but I have no idea as to what the humidity levels are. I only have a cheapo thermometer in at the moment, my girls haven't complained so I wasn't concerned. Now I'm curious. It does get humid and muggy during the summers here, I run a window fan though and run my lights at night: A/C seems like overkill from a power usage standpoint.
The filter is a Can Filter 33. It says its rated at a max of 400cfm scrubbing, I have my s&p wired to run on the low setting, which is 200cfm I believe. Also, I have a toggle switch set up so I can switch the fan on High, which I have a fan speed adjuster set up on to the lowest level. Must be like 150 cfm at that point and thats how I usually run it. Also, this filter is 10 months old, but like I said before, I seem to remember this happening last time I flowered as well. I have ZERO issues aside from this 20 or so minute time frame.

No one has ever encountered this before? It just doesn't make any sense, there is NO odor at any other point of the day! wtf! lol. Thanks again for the help guys!

 

[Green lung]

I have noticed right after lights off I have noticed the same thing in my tent, but it doesn't bothere me that much. I think the plant is releases more pungent odor when lights go off. it more of a planty smell than a bud type smell right?



Those pinholes on your flexy duct arn't actually holes it just where the reflective material rubbed off and the duct is a little transparent.


other than getting a stronger filter i don't see anything more you can really do

 

[Green lung]

is the smell just like when you open the cab or is the smell coming out of your exhaust?

 

[Lurking4Years]

Green lung: Yes, thats exactly right! Its more of a planty smell than a stanky herb smell. I have a window fan bringing in cool night air in that room, and go in to shut it off right at lights off. And I actually assumed it was from some kind of plant outside, like as the sun hit it or something. It was just the other day that I noticed it when the windows were shut, and I freaked out. And yes, it is coming through my exhaust. I don't open the cab at all when I smell it. It ONLY happens right when the lights shut off automatically, and it lingers for maybe 20 minutes. Is that what you're encountering as well?

Thanks for the ducting info, I thought that's what it was at first; I couldn't see how ducting could just get that many holes from being moved around a little.

 

[Green lung]

Only other thing is make sure you tape up all the seams on your reflector, ducting ect. so there is no "dirty" air sucked out without going through the filter.

Can 33 should be enough for a 400 cab I figured even with the extra smell, but maybe if it concerns you might want to think about getting a stronger filter.