Scrubber isn't scrubbing - what the?

Hey all,

My first indoor grow. Set up in a sealed basement room I built. Using a combo package 6 inch 420 cfm inline fan and charcoal canister filter. Definitely have a negative static pressure in the room.

I'm into week four, still in veg. The garden is getting very pungent already. Came home from work today and the moment I walked into the house I could smell it.

I've taped all seams with metal foil tape, checked my connections and the ducting (insulated six inch flex duct), and cannot find any leaks anywhere. I even replaced that section of duct tonight in case it had a leak. But no joy - when I stick my face into the exhaust I can smell the garden.

The scrubber has only been in service these four weeks. Supposed to be good for 18 months. Did I get a dud? Maybe something that had been sitting around a long time? It was wrapped in plastic in the box when I got it.

The only other thing that comes to mind is the fan casing is pulling in unfiltered air. But I don't see where it could do that.

As this is my first experience with these, am seeking wisdom from those in the know. Thanks for any info you can offer.

Just wanted to add - I taped the seam on the inline fan last night after posting this. Smell is still coming out of the fan exhaust. I love that aroma, very heady, but it's not practical circulating it throughout the house.

All I can come up with is either the air is moving through the filter too quickly, or the filter is undersized for the application. I've emailed the supplier with questions, but if past history is any indicator, I won't get much of an answer.

If it helps any, 3 adjacent sealed rooms, 1340 cu ft total, with the 420 cfm fan exhanging the air every 3 minutes or so. This is really making me nuts, I've searched and searched and have not found any answers. If this unit had been in service for awhile, ok, replace the filter, but almost new and not removing the odor, I'm stumped.

Anybody? Bueller? Anyone? Anyone? Please help a newb out.

if you move too much air through a small filter it will have negative effects.
They are rated for a given CFM if you over do it it will not be able to absorb the smell.

MSPB

Thanks for the reply moneyshotpb. From what I've been reading, you are absolutely correct. Also it would seem that only 100 milliseconds, or 0.1 seconds of contact is required with the carbon for it do the job.

The fan/filter in this case was sold as a package. I assumed (big mistake perhaps) that the supplier did his homework in offering this package, in matching up the fan with the filter.

This morning I turned to the fan itself. I noted that the junction box was not fitted to the fan casing very well, with a significant gap on one side. I unplugged it and opened the junction box, then removed it from the fan casing. I removed a little material from the box with a file, but I couldn't remove enough to provide a good seal. So I reassembled it and foil taped the seam of the box to the fan. What was noteworthy here was that some the screws on the terminal strip were somewhat loose, which could have led to problems down the road. A loose connection means higher electrical resistance, which leads to heat, which increases the resistance, which increases the heat, etc. An electrical fire in the grow room is not a happy thought. So I'm glad I at least found and rectified that.

Alas, the problem continues. I can only conclude at this point that the filter they shipped me was pretty much spent, as far as the activated carbon goes. From a google search, the shelf life of activated carbon is two to three years. And while spent activated carbon can be reactivated, using steam and a chemical scrubber, this is an industrial process.

Going to beat on the supplier to replace the filter. If they won't do that, I will out them and shop elsewhere. A can 66 looks pretty good at this point, but will research further.

One last question - am I naive to think that the filter will remove ALL of the odor?

Thanks for any help you can offer. :)

How high is the humidity? Humidity screws up a carbon scrubber,the carbon absorbs the moisture and won't clean the air. Have you looked into UV ozone scrubbers. They seem to work quite well. You just can't put them in the same room as the plants. You could install one in your venting tube.
Hydroponics : TITAN OZONE GENERATOR : Titan Ozone Generator

Quote:

---

A loose connection means higher electrical resistance, which leads to heat, which increases the resistance, which increases the heat, etc.

---

Not many folks think about that. It applies also to your wall outlets, extension cords, multi-outlet strips, etc. Any connection that's not a good, tight contact can start heating up. Eventually the connectors become brittle and won't even "conform" well to the mating connector. But you know that already...

I'm curious what brand fan / filter combo you've got. The combo sounds like a Can Fan setup but their workmanship is excellent. You should not see what you've described with their products, IMO.

Maybe some pics or a diagram of how exactly your airflow's routed, and where your components are, would shed some light. Some folks just have a scrubber sitting in the room doing its thing, separate from the ventilation system. If you pump air out of a room like that before the scrubber can clean it, it'll smell.

Others pull the air out of the grow room through the filter. Is this how you've got it arranged? I'm confused about the "other rooms" and where the fan is. You pushin' or pullin'?
Regards, Hermie.

And KW420 is right. Humidity can affect a carbon filter.

Thanks for the replies. Appreciate you trying to help me out.

Humidity has ranged from 38% (very cold and dry outside) to just past 50% today (warm and humid outside), normally (over the last four weeks) 44 to 45 percent. I read where humidity past 70% can be a problem. I have a dehumidifier waiting in the wings, but thus far haven't needed to hook it up yet. Temps range from 68 degrees (lights out overnight) to a high of 77 degrees (nearing end of light cycle).

The setup is three adjacent sealed rooms, each 8 by 8 by 7 ft high. Cool air is drawn from one end through a 12 by 12 register, then through a series of registers passes through the middle and then to the end room. I have doors between rooms, but haven't had to isolate anything yet, so the doors are open and the airflow passes freely from room to room. The end room has the filter/fan setup. I added a pair of home-made mufflers to the intake and exhaust to deal with the noise of the airflow. I am pulling through the filter. The rig is mounted up near the ceiling to exhaust the warm air out. All metal ducting seams in the elbow and my mufflers are sealed with metal foil duct tape. All connections are properly secured with hose clamps. For what it's worth, I worked with flex ducting a fair bit during my days as an aircraft mechanic, so I was taught how to do it right.

The arrangement is - carbon filter, six inches of six inch insulated duct, muffler, 45 degree elbow, 18 inches of insulated duct, inline fan, four feet of insulated duct passing through the wall, exhaust muffler. The fan is about six inches from the wall; where the duct passes through the wall the hole is sealed around the perimeter of the duct.

I'm somewhat reluctant to name names, as I don't want to slur the supplier should the problem be my own, but I purchased the fan/filter from High Tech Garden Supply. This is their GrowBright 6 inch fan and filter combo. While they sell Can Fan filters, I don't think the one in the combo is one of them. If I remember correctly, there was no mfr name on the box the filter came in, and there are no identifying marks on the filter itself. The filter is supposed to be a "packed bed" design. It does come with a prefilter, which was installed when the filter was hung up. Link --> High Tech Garden Supply

I've wondered if the mufflers I've added are a problem, but cannot fathom why this would be. I detailed the muffler construction in another thread a few posts down --> http://boards.cannabis.com/growroom-...-proofing.html

Been thinking this up and down and sideways, and am drawing a blank. I could see an unsealed room emitting odors, but that's not the case here. The smell is definitely coming from the fan exhaust.

Going to call them tomorrow and see what they can tell me. Have to find a fix very, very soon.

Edit - the ozone filter is something to think about. Thanks for that.

Don't know if this is practical for you, might be a bitch to unmount things. But if you put all your plants in one room and sorta seal that room (doesn't have to be airtight at the molecular level :D) you could assemble just the fan / filter combo and run it as an internal recirculating scrubber --not venting it to outside the grow area, if that makes sense. Just the fan pulling stinky room air through the filter continually, and recirculating it within the room.

Now, you can't keep this up forever; you'll need to eventually vent some fresh air (CO2) into the room, and vent out the heat produced by the fan motor. But this shouldn't take that long, maybe an hour to tell if it's working.

If your fan's turning, and air's getting sucked in through the filter, your fan's OK (unless your housing's still leaking). If your filter's good, it should be able to handle the smell from 8-12 one-month-old plants, depending on strain, size, etc. within that single sealed room. If the fan/filter combo suppresses your odors, start reassembling your ventilation system one section at a time until you locate the component that's causing the problem.

If your filter's not breathing real freely your system may be creating enough of a vacuum to pull stinky air into the ductwork AFTER the filter, especially if you're overdriving the filter. That seems like the only way smells could be getting in there, unless the filter's just not removing them to begin with.

Now, if you've got a goodly number of plants going, you may just need that Can 66 (or more). I've been abusing the hell out of a Can 33 (with a 424 cfm on a speed controller) for a year and a half and it's hanging tough. :thumbsup:

FWIW, HTG seems a reputable firm and the "store brand specials" are cost-effective. Maybe you can trade up. Filters are heavy to ship, though.

HTH, Hermie

Thanks Hermie. Some good points there. Right now, I have 18 plants, grown from bag seed. I expect about half of them will turn out to be males, so am trying to get enough started to account for that.

And I've come to see my terminology is flawed. I'm not using the filter as a scrubber, but as a vent filter.

After sleeping on it, I went looking at Can Filters today. And I believe I see the issue here. I don't believe I have a leak in the system. I now am of a mind that the HTG no-name is just not enough for my application. Comparing the HTG to a Can Filter 66 - 9.5 inches diameter, 18 inches long, 17 lbs, vs the Can 66 at 12 inches diameter, 26 inches long, 44 lbs. I'd guess about double the carbon in there, if not more. Not a slam at HTG's filter. Just seems I need more horsepower, so to speak, to do the job.

HTG is closed on Mondays - going to speak to them tomorrow about trading up. Have a feeling they won't go for it, but will see what they say. I have to do something, no question. The whole basement stinks now, and it is noticeable when you walk into the house.

Should have gone with a Can Fan/Can Filter 66 combo from the beginning, I suppose, in hindsight. Live and learn, but often the learning experience is a pain in the wallet.

Will post an update, in the hopes it will help other newbs out there.

Thanks all for replying. Appreciate it very much. :)

Hey all,

The mystery is solved. I got a reply to my email from HTG this morning. They seemed to know what the issue was right away.

"If you shake the filter, does it rattle? The carbon is supposed to be packed real tight, shouldn't make a sound if you shake it."

I came home from work and shook it. It rattled alright. Big time.

Called them and they are exchanging it for free. Asked me to send the old one in, and they'll send me a new one. Um, no - then I'll have no filtration at all for about a week, and I'm supposed to have company over tomorrow night. So I've arranged to buy another one, and they will credit me when they get the defective one back. Overnighting the new one was another ten bucks, so I went for it.

Tomorrow evening will be burning a lot of incense and running around spraying Febreeze all over, but the issue is resolved. Lesson learned.

Thanks for all the help on this one folks. ;)

Another update...

Received a replacement carbon filter today. Shook it, it rattled a little. Not this sh*t again, I thought. Hooked it up, it seemed to be working, came downstairs an hour later, and.. I could smell the garden again.

Son of a...

Emailed them and told them I wanted to trade up to a Can Filter 66. Awaiting a response.

Bottom line - after two tries, I give up on their generic stuff. Not up to snuff.

Will update as this evolves. :wtf:

*Update*

This started out pleasantly enough, but HTG has now changed their tune. They will give me a credit on the replacement filter, meaning I will get the money back on the second filter I purchased, but won't credit me on the original purchase. So I'm out the 90 dollars on that, and it doesn't work as advertised.

Add to that, I'm now seeing their "Growbright" inline fan is leaking oil. Finding oil droplets at the fan exhaust outlet. Looks like hydraulic fluid. I don't think this fan is long for this world. So now I'm out 200 dollars total.

I'm done with these guys. Not impressed with the quality of their products. Budget prices, yes, but the old adage "you get what you pay for" has never been more spot on. I should know better - whenver I buy crap I almost always end up spending more on quality items later. Better to buy the right gear at the beginning.

Sigh...

Going to go with a Can Fan 6 HO (440 cfm), and Can Filter 66, for odor control and ventilation, and a Can Fan 6 (260 cfm) for venting the HPS lights. Mo money, mo money, mo money, but no more grief. End of issues.

Cool dude hope it works out sorry about you getting screwed out of 90 bucks.. Hope my carbon filter dosen't give me any problems.

FWIW, got the Can Filter 66 today. For the moment it's hooked up to the HTG fan, but the Can Fans should be arriving tomorrow. My bud dropped by to help me hang the filter, and he smelled the garden very clearly when he walked in, and he was smoking a cigarette...

When I connected the filter to the fan I immediately noticed the fan was significantly quieter, and moving a lot more air. However, as it has leaked oil out, it's going in storage for emergency use.

Two and a half hours later, came back from walking the dog. Went in, and ... no smell at all. Anywhere in the house. Very cool. Ultimately all the air in the house goes through that filter... a nice bonus. Now that's how I expected this thing to work going in.

Cannot recommend the HTG house brand fan/filter combo to anyone. The filter doesn't do diddly, except restrict airflow significantly, and the motor leaking oil pretty much destroyed any remaining faith in their product. Now my experience may be unique, but any piece of gear I have to go through several of to find one that works, is a waste of time for me. Save your cash, buy the good stuff, and you can't go wrong. :thumbsup: