Does A Carbon Filter Remove 100% Smell

haze010 said:

Yep this is exactly what im trying to preach. Anyone who has their space discovered by smell has severely f'd up. It should be the easiest thing in the world to control and the absolutely last thing to ever get you caught. To be incredibly blunt the only way smell is an issue is if you are just lazy or stupid. Its a relatively inexpensive thing to do as well and in my mind is equally important as providing the right nutrients and light to the girls.

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I would have to strongly agree with haze010. $160 dollars for peace of mind that no smell or leakage of smell to my neighbors or even guests in my house is priceless. You will have a horrible smell during flowering and I don't care what anyone says but no product including ONA GEL will eliminate the smell 100% that your plants give off during flowering. I can tell you that prior to about 4 weeks ago I didn't have a carbon filter and every time I would walk into my place "smack" right in the face. I couldn't have guests over or anything. It also creates great airflow in your tent and removes a lot of unwanted things from your tent like mold spores. If you're looking into a nice carbon filter system I'd be happy to share what I bought and know works.

SydneyGirl12 said:

I would have to strongly agree with haze010. $160 dollars for peace of mind that no smell or leakage of smell to my neighbors or even guests in my house is priceless. You will have a horrible smell during flowering and I don't care what anyone says but no product including ONA GEL will eliminate the smell 100% that your plants give off during flowering. I can tell you that prior to about 4 weeks ago I didn't have a carbon filter and every time I would walk into my place "smack" right in the face. I couldn't have guests over or anything. It also creates great airflow in your tent and removes a lot of unwanted things from your tent like mold spores. If you're looking into a nice carbon filter system I'd be happy to share what I bought and know works.

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Yes and as i said if anyone here cant afford something like a Phresh filter i'd be happy to guide you on how to do it on the cheap. It wont look pretty like one of those but it will still work and be cheaper.

burninjay said:

I should add that I use home-made filters that I feel are pretty well put together, but I can only assume that a can filter from the hydro store would maybe work a bit better.

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Not really it just means you need to tweak things a bit. The only advantage a can filter has is that they have the knowledge and testing to rate the CFM for it whereas a homemade jobby is trial and error till you get the right balance of airflow and weight of carbon in it. What youre describing means not all the air from your grow is going thru the carbon before entering the rest of your apartment. The most common failure in a DIY like that is just not powerful enough of a fan to create the airflow you need to maintain a negative pressure environment. If it was not enough carbon you would likely always notice a faint smell, where its only sometimes its basically the cfm travelling through your carbon isnt high enough so when you open the door some of the air comes out the door. A negative pressure environment means you should notice the fabric sides of your tent are sucked inward and tight, air is escaping thru your carbon at a higher pressure/rate than it can enter your room.

Hope that explains it.

texasjack said:

In my experience, no. There is still a funk coming out the vent.

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If you smell anything out the vent that means you dont have enough carbon or the carbon in it is all used up. It doesnt last forever and you need to replace the carbon eventually.

McStrats said:

I work in industrial air handling where we use carbon for plastic extrusion applications (very stinky). The amount of carbon is dictated by the room size. You also don't want too many cfms as the odors needs "dwell time" in the carbon. Use a VFD and dial back the cfm and find the sweet spot.

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Exactly, if your carbon filter isnt eliminating 100% of the smell all the time then there is an imbalance somewhere you need to tweak. A bit of trial and error on cfm, weight of carbon ect till you find what works for your volume of room. A proper carbon filter will 100% scrub the air of all smell if its calibrated properly.

I would argue its impossible to have too strong of a fan. If the air is whipping thru the carbon too quickly because of a powerful fan within reason. You just need more carbon in there and pack it more dense so the airflow through it is more restricted. Its just a matter of finding the correct balance and then maintaining that balance.

Now if you were to attach something like this
http://www.hazmasters.com/Omnitec-OmniAire-2200C-Negative-Air-Machine
for a 2x2 closet, then yah thats too much of a fan, that thing is for scrubbing an apartment size area of like an 800squar foot apartment. Thats the kind of gear and filters i work with on a daily basis.

haze010 said:

Exactly, if your carbon filter isnt eliminating 100% of the smell all the time then there is an imbalance somewhere you need to tweak. A bit of trial and error on cfm, weight of carbon ect till you find what works for your volume of room. A proper carbon filter will 100% scrub the air of all smell if its calibrated properly.

I would argue its impossible to have too strong of a fan. If the air is whipping thru the carbon too quickly because of a powerful fan within reason. You just need more carbon in there and pack it more dense so the airflow through it is more restricted. Its just a matter of finding the correct balance and then maintaining that balance.

Now if you were to attach something like this
http://www.hazmasters.com/Omnitec-OmniAire-2200C-Negative-Air-Machine
for a 2x2 closet, then yah thats too much of a fan, that thing is for scrubbing an apartment size area of like an 800squar foot apartment. Thats the kind of gear and filters i work with on a daily basis.

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The main component in an air scrubber is a HEPA (particulate filter) - since you aren't filtering particulate the HEPA isn't doing anything for odors. You can indeed also have too strong a fan for carbon. For plastic extrsion applications I usually dial back the CFM by 50% compared to ambient dust capture applications. Too many CFM's means too little dwell time in the activated carbon.

McStrats said:

The main component in an air scrubber is a HEPA (particulate filter) - since you aren't filtering particulate the HEPA isn't doing anything for odors. You can indeed also have too strong a fan for carbon. For plastic extrsion applications I usually dial back the CFM by 50% compared to ambient dust capture applications. Too many CFM's means too little dwell time in the activated carbon.

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If you use a prefilter as you should it acts just like the hepa.

haze010 said:

If you use a prefilter as you should it acts just like the hepa.

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A HEPA filters down to .5 micron @ 99.97% eff - a prefilter doesn't do that at all. You don't need a HEPA for growing cannabis. You use a HEPA if you have an airborn carcinogenic dust like asbestos.

Not all of the chemicals put off by the plant are adsorbed by carbon. There is a faint odor remaining, it's just not a weed odor. It's kind of sweet, smells a bit like drunk breath or acetone to me. Unless the person has experience stealth growing they wouldn't know it was Cannabis.

Remember that peoples sense of smell/taste varies quite a bit. Not only is natural talent involved but training improves the ability to discriminate and and describe smells/tastes.

The people that are saying it removes 100% of odor and absolutely nothing detectable emerges from the carbon filter just don't smell it themselves. Carbon is very highly effective and absolutely required for stealth but it is not 100%.

Im not trying to be a jerk here guys, but i know what im talking about. Im a HAZMAT professional with almost two decades of experience. To get initial certifications on all the things i deal with requires over 200 hours of training and you must complete a minimum of 60 hours a year to maintain it. I have dealt with everything from basic mold and asbestos remediation all the way to liquid propane in a pressurized enviroment and biomedical hazards.

You dont have to believe me, i'll just link the basic orientation training guidelines put out by one of the leading manufacters of air scrubbers and neg air machines.

Carbon filtration can and will eliminate 100% and gaseous contamination. There are many varieties of cheap activated carbon that arent pure and can lead to byproduct smells like observe&report describes.

If youre not using a prefilter in your machines, regardless if its for a particulate situation (fibres in the air like mold, asbestos, dust, pollen ect ect) or a gaseous situation (smells, airborne viruses, fuels like propane methane ect, carbon monoxide) then youre doing it wrong. There is absolutely no situation you should ever use an air scrubber without a prefilter.

Just because your situation didnt eliminate it 100% doesnt mean carbon cannot eliminate 100% of gas contamination.

If it didnt work id be dead 2 decades ago.....

Basic documentation from the manufacturer.
https://www.drieaz.com/uploads/deca/gtas.pdf

If anyone is super interested this is only a fraction of the training ive recieved.
http://www.roninrescue.com/safety-training/hazmat-training/

You may have dealt with a handful of carbon filtrations, ive dealt with literally thousands.

haze010 said:

Im not trying to be a jerk here guys, but i know what im talking about. Im a HAZMAT professional with almost two decades of experience. To get initial certifications on all the things i deal with requires over 200 hours of training and you must complete a minimum of 60 hours a year to maintain it. I have dealt with everything from basic mold and asbestos remediation all the way to liquid propane in a pressurized enviroment and biomedical hazards.

You dont have to believe me, i'll just link the basic orientation training guidelines put out by one of the leading manufacters of air scrubbers and neg air machines.

Carbon filtration can and will eliminate 100% and gaseous contamination. There are many varieties of cheap activated carbon that arent pure and can lead to byproduct smells like observe&report describes.

If youre not using a prefilter in your machines, regardless if its for a particulate situation (fibres in the air like mold, asbestos, dust, pollen ect ect) or a gaseous situation (smells, airborne viruses, fuels like propane methane ect, carbon monoxide) then youre doing it wrong. There is absolutely no situation you should ever use an air scrubber without a prefilter.

Just because your situation didnt eliminate it 100% doesnt mean carbon cannot eliminate 100% of gas contamination.

If it didnt work id be dead 2 decades ago.....

Basic documentation from the manufacturer.
https://www.drieaz.com/uploads/deca/gtas.pdf

If anyone is super interested this is only a fraction of the training ive recieved.
http://www.roninrescue.com/safety-training/hazmat-training/

You may have dealt with a handful of carbon filtrations, ive dealt with literally thousands.

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And just for shits and giggles i'll walk around my works storage warehouse tomorrow snapping pics of equipment like a 28 foot long hazmat trailer with built in triple chamber entrances and decontamination showers. Or an air compressor larger than the average truck. I'll even hold up a sign saying RUI just in case you think its internet stock photos,

Nobody cares about how long your hazmat trailer is.

What prefilters do you refer to? The white covers that come the carbon filter, or is it something else?

haze010 said:

Im not trying to be a jerk here guys, but i know what im talking about. Im a HAZMAT professional with almost two decades of experience. To get initial certifications on all the things i deal with requires over 200 hours of training and you must complete a minimum of 60 hours a year to maintain it. I have dealt with everything from basic mold and asbestos remediation all the way to liquid propane in a pressurized enviroment and biomedical hazards.

You dont have to believe me, i'll just link the basic orientation training guidelines put out by one of the leading manufacters of air scrubbers and neg air machines.

Carbon filtration can and will eliminate 100% and gaseous contamination. There are many varieties of cheap activated carbon that arent pure and can lead to byproduct smells like observe&report describes.

If youre not using a prefilter in your machines, regardless if its for a particulate situation (fibres in the air like mold, asbestos, dust, pollen ect ect) or a gaseous situation (smells, airborne viruses, fuels like propane methane ect, carbon monoxide) then youre doing it wrong. There is absolutely no situation you should ever use an air scrubber without a prefilter.

Just because your situation didnt eliminate it 100% doesnt mean carbon cannot eliminate 100% of gas contamination.

If it didnt work id be dead 2 decades ago.....

Basic documentation from the manufacturer.
https://www.drieaz.com/uploads/deca/gtas.pdf

If anyone is super interested this is only a fraction of the training ive recieved.
http://www.roninrescue.com/safety-training/hazmat-training/

You may have dealt with a handful of carbon filtrations, ive dealt with literally thousands.

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haze010 said:

Like i said if your cfm exchanges it at least 4 times an hour you will have zero issue. 240 cfm for 800 sq feet is about 5 an hour. As long as u keep the fan clean, usually by a prefilter u should ha
ve negative air pressure no problem. The reason a clean fan matters is cause debris will add friction and slow it down.

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Observe & Report said:

Nobody cares about how long your hazmat trailer is.

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Im trying to be a nice guy and give professional accurate advice on the one damn thing around here i do know. Ive asked for help and recieved it repeatedly around here with a variety of things, this is the one thing i can offer expert advice on. Some ppl would rather doubt question and shit on accurate info if it disagrees with their opinion than accept any disagreeing information despite evidence.

The photos would just show that im not just another internet bs machine and actually make my living in this industry, i could easily produce pictures showing millions of dollars worth of equipment that clearly say its for hazmat response and noone would ever have access to otherwise.

Dont be butthurt cause i corrected you, im trying to help ppl be able to do things without ever getting caught. All activated carbon is is simply charcoal, when you have that acetone smell they are using an accelerant in the process of making it to be able to make it faster and cheaper and youre getting a residue in the end product.

When EMT's or firefighters respond to a dangerous situation where they must evacuate people they will either be using contained air breathing systems with oxygen tanks or a battery powered full face PPE system that has can filters on it that have both a HEPA filter for particulate and a carbon filter chamber. An oxygen tank is providing your own personal pure air. Thats not always an option depending what the hazard because pure oxygen will add fuel to a fire.


The best activated carbon uses no accelerants in the process and are made from organic things like coconut husks or bamboo but it can be as much as 15x more expensive. Having the absolutely most pure carbon is incredibly important when you are using it for filtering out air you are directly breathing in, you dont want to breathe in any residue from a fuel accelerant as that alone can cause damage to your lungs depending what was used. If the carbon is just using to filter your growing space that doesnt matter and cheaper product that does have fuel byproducts is absolutely fine and has no bearing on the end result.

Heres a small can style filter that attaches to a full face PPE mask and uses absolute pure carbon to filter out deadly gases from the air, i can personally say filters like that have kept me alive in situations where if i didnt have it on i would have severe lung damage.
https://www.sylprotec.com/en/3m-respirators/3258-3m-organic-vapors-and-acid-gases-cartridge-with-hepa-filter-60923-2-units.html
Something like that has to have the best carbon available and they actually lab test random batches to ensure its only carbon right down to its element form.

This is a filter that is for just smell only, like if you were a guy who worked in a sewage treatment facility and had to go into a vat container of sewage that was harmless but very smelly all you would need is something like this.
https://www.pksafety.com/mo24ovduma.html
So if you ever have to clean your own septic tank, buy a box of those mask filters and you can wade knee deep into sewage and have zero odours actually hit your nose. It will be the best $100 you ever spend.

Not all carbon is created equal.
An example of the high quality stuff that will absolutely have no byproduct smell and is certified food grade.
http://www.ebay.ca/itm/100-Premium-Activated-Bamboo-Charcoal-Powder-For-Teeth-Whitening-Toothpaste/291920103212?_trksid=p2047675.c100005.m1851&_trkparms=aid=222007&algo=SIC.MBE&ao=1&asc=20140620091118&meid=076efc7f94b3416ca35135c562929373&pid=100005&rk=2&rkt=6&mehot=pp&sd=291982618866

The stuff you find in most filters thats not for an air breathing device is made simply by dumping fuel on wood waste from things like a pulp mill and is more than adequate for masking the smell of your pot plants but can smell like acetone.

I could spend all day educating someone on air breathing filtration, and in fact i do and am paid very well for it. Is there anything else you would like to know?

Philip-O said:

What prefilters do you refer to? The white covers that come the carbon filter, or is it something else?

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Yes, most carbon filters come with a prefilter already attatched and should look something like this.
https://www.fosterindustrial.co.uk/adflo-pre-filter-836010

Not all do though and if you have one that doesnt, buy a prefilter. It will extend the life of your carbon tenfold and will prevent any airborne contaminants from entering your machine. It actually matters in a growing space because the last thing you want is powdery mildew spores in your growing environment.

haze010 said:

All activated carbon is is simply charcoal, when you have that acetone smell they are using an accelerant in the process of making it to be able to make it faster and cheaper and youre getting a residue in the end product.

The stuff you find in most filters thats not for an air breathing device is made simply by dumping fuel on wood waste from things like a pulp mill and is more than adequate for masking the smell of your pot plants but can smell like acetone.

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You say most filters for Cannabis grows are made from wood pulp, so which are pure and don't have residual accelerant?

Observe & Report said:

You say most filters for Cannabis grows are made from wood pulp, so which are pure and don't have residual accelerant?

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Well no, i said cheaper carbon is usually cheaper because its not pure, its made cheaply. And when you had an acetone smell coming out your exhaust thats obviously from an accelerant (fuel of some kind) that they use to speed up the charcoal process making it cheaper. Carbon used in air breathers has standards and has to go thru testing. Some carbon designed for aquarium use is that way too. Other activated carbon has no testing or requirements and is WAYYYY cheaper. Most companies making products that dont neccesarily need that go for the much cheaper source. I know for a fact that pulp mills turn their waste into activated carbon tho and its the cheap stuff. Some filter companies like Phresh use the top shelf good stuff and they advertise their standards and what they do, its part of the reason they are more expensive that most. I cant tell you what companies source where but if you look thru anywhere you can buy carbon (pet store, ebay, ect) you will see different grades of carbon, everything from food grade like the link i showed, to stuff with no standards.

I couldnt tell you who uses what other than i know for sure Phresh uses the good stuff and its why ppl consider them the best filtration on the market for growers using can filters. Generally if someone doesnt advertise the carbon that they use, its likely the cheap stuff thats not going to be totally pure.
http://www.phreshfilter.com/

The thing is if you already have a can filter which it seems you do, you dont want to buy a filter, you just want to buy quality carbon and change it yourself. Any pet store walmart ect as i explained before just dont go for the cheapest thing on the shelf and read what its for. When i recommended carbon i recommended fish aquarium carbon cause its high quality(if not it would kill your fish) and sold in large amounts.

Somethign like this available at walmart.
https://www.walmart.com/ip/AquaTech-Carbon-Fish-Aquatic-Pets/10313138

That's funny you should recommend Phresh because that is exactly the filter I'm using.

I did a little experiment, which I should have done a long time ago. I took my spare filter and fan that I keep for trimming and emergencies and set it up as a scrubber in a different room, far from the grow. Same smell coming out of the filter. So what I'm smelling isn't something from the Cannabis that's getting by the filter, it's from the filter. Don't latch onto acetone, I wouldn't say that is a good description of what I'm smelling. They probably use phosphoric acid to activate the carbon but I don't know what that smells like.

So now I correct myself and say I don't know if carbon gets rid of 100% of flowering Cannabis odor because I haven't experienced it and the filters I've been using apparently have their own odor. I do know that carbon is not 100% effective on all molecules. Here is one source on that, there are many others because it is not controversial.

http://www.lenntech.com/library/adsorption/adsorption.htm

edit; also, I'm not using Phresh filters any more, I'll keep my spare for trimming but I'm going to try to find something else for the cabinet.

I replaced my Phresh filter with a Can 33 and now there is no smell coming from the filter. I've had four Phresh filters over the last few years and they all had the same odor. It smells to me somewhat like drunk breath. I thought it was perfectly normal for some small odor (not weed odor) to come from the filter because everyone recommends Phresh but apparently they aren't up to snuff!

So I was wrong when I said carbon doesn't get 100% of the weed smell, it does for me at least. However, I do not recommend Phresh filters because they emit their own odor

Observe & Report said:

I replaced my Phresh filter with a Can 33 and now there is no smell coming from the filter. I've had four Phresh filters over the last few years and they all had the same odor. It smells to me somewhat like drunk breath. I thought it was perfectly normal for some small odor (not weed odor) to come from the filter because everyone recommends Phresh but apparently they aren't up to snuff!

So I was wrong when I said carbon doesn't get 100% of the weed smell, it does for me at least. However, I do not recommend Phresh filters because they emit their own odor

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Okay i respect that, i've never used them i said most ppl recommend them as the leading. I make my own because i have access to airbreather grade carbon at cost.

Its all about the carbon inside.

And im well aware carbon doesnt remove 100% of all molecules but we are talking about smell in a grow not a hazmat situation with carbon monoxide. For purposes of smell from a grow you should have 100% removal of plant odor, whatever the residue smell u were getting its from the carbon itself. I would just go buy some fish aquarium carbon replace and be done with it, should stop that issue completely. Needless to say i was wrong about phresh but what i said does apply.

Really you wasted $ by buying a whole new can filter, next time just replace the carbon yourself.

I respect that when you were wrong and realized it freely admit it, most around here wont do that.