Hi I'm growing 6 plants in a 1.2 x1.2 x2.0 mtr2 tent with a 600watt hps light can anyone tell me what the best size carbon filter and exhaust size wud be best aswell as intake I know intake must be smaller to create neg pressure I'm askin as I live in a downstairs flat growing in Spare room (big) and I'm worried the people that live above may smell it so any1 tht can tell me ways too reduce smell is really helpfull thanks for reading this
Smell control
- Thread starter Jmc1
- Start date
contraptionated
New Member
You would definitely leak the smell throughout the entirety of the dwelling if you exhaust into the interior of the wall. Also, take Zagons advice and don't use an intake fan if you could simply have passive intake holes 4x (not 2x) the square inch area of the exhaust opening. For example, a 10" can fan needs a 14" duct at the outlet (at least, preferably 16" if there is a bend in the trunk) to emit 800 cfm. If you thought you could match a 4",6",8", 10" (any diameter) fan with the same size duct you would cut the max cfm by approximately 55-60%. If there's an elbow in the run, you'll be down to 20-25% of the max cfm the exhaust fan could put out.
The theory that one could use (for example) a 6" fan for intake (fresh air supply) and a 10" fan for exhaust is a fatal error. Here's why: a 10" can fan (800 cfm) sucking through a CanFilter 150 and pushing air through a duct silencer and 10-15 feet of straight horizontal 10" flex duct will only expel 350 cfm (I know this as fact because I have 3 of these exhaust lines set-up identically the same side-by-side and I used a velocity meter at the outlet vents and they all release at approximately 350 cfm). If I had a 6" fan pulling air in with no duct connected on either side (typical intake fan set up) I would be taking in more fresh air than I could release because a 6" Can Fan is rated higher than 350 cfm.
It is only in a rare and exceptional case that you would need an intake fan. When you have a very small opening that fresh air can be taken from and it does not equal 4x the area of the exhaust outlet. You would then need an air velocity meter to be certain that you have a negative air pressure because you don't want to leak odors or heat to the immediate surroundings.
The theory that one could use (for example) a 6" fan for intake (fresh air supply) and a 10" fan for exhaust is a fatal error. Here's why: a 10" can fan (800 cfm) sucking through a CanFilter 150 and pushing air through a duct silencer and 10-15 feet of straight horizontal 10" flex duct will only expel 350 cfm (I know this as fact because I have 3 of these exhaust lines set-up identically the same side-by-side and I used a velocity meter at the outlet vents and they all release at approximately 350 cfm). If I had a 6" fan pulling air in with no duct connected on either side (typical intake fan set up) I would be taking in more fresh air than I could release because a 6" Can Fan is rated higher than 350 cfm.
It is only in a rare and exceptional case that you would need an intake fan. When you have a very small opening that fresh air can be taken from and it does not equal 4x the area of the exhaust outlet. You would then need an air velocity meter to be certain that you have a negative air pressure because you don't want to leak odors or heat to the immediate surroundings.
Tassie1619
Member
Totally Disagree if no disrespect. a 125mm Fan and Filter Combo WOULD be More then enough. but you definitely! want a small fan for intake, your just risking mould in latter stages of the cycle. And environment is number 1 when it comes to growing,
contraptionated
New Member
What if that small exhaust fan is not working up to its max cfm rating? Unless you enlarge the duct at the exhaust fan outlet you will not get the cfm rating of the fan (minus the static pressure loss of the filter and duct length of course).How do you know how much air is being expelled? All you did was"disagree". I did a 3x redundant live case study with numbers that make sense. If you want to refute my experiment, you need to (at the very least) explain why. You can't just say "it's more than enough". Go read ACCA Manual D then you will understand why almost nobody gets even half of the cfm output of their exhaust fan filter combo.
When you do read it, look for the table that lists the max cfm output of various diameters of round flex duct. You will then understand why the "2 size smaller intake fan/ exhaust fan" ventilation concept creates positive pressure 99% of the time.
By the way, we all know "environment is number 1 when it comes to growing". That's why I don't disagree with people based on no facts whatsoever. I don't want people screwing up their grow environment because of confidence. That's why I read and experiment (on a very large scale mind you) with grow houses that are probably taking more electricity in a month than what you are going to use in a year.
Then again, I need not argue with you because you don't know how to debate with facts. That makes you a moron.
When you do read it, look for the table that lists the max cfm output of various diameters of round flex duct. You will then understand why the "2 size smaller intake fan/ exhaust fan" ventilation concept creates positive pressure 99% of the time.
By the way, we all know "environment is number 1 when it comes to growing". That's why I don't disagree with people based on no facts whatsoever. I don't want people screwing up their grow environment because of confidence. That's why I read and experiment (on a very large scale mind you) with grow houses that are probably taking more electricity in a month than what you are going to use in a year.
Then again, I need not argue with you because you don't know how to debate with facts. That makes you a moron.
contraptionated
New Member
I agree. An ozone generator is good to use in conjunction with a separate carbon filter set up Although, me personally I don't like them for stand alone odor removal because the carbon filter/fan combo is less likely to stop working unexpectedly and the ozone needs a huge contact chamber to work as well as a properly sized carbon filter/ fan combo.
I've had my share of side by sides with 15,000 volt ballast ozone generators and they did not achieve 100% odor elimination the way the carbon filter did.
Even though the element for an ozone generator doesn't need to be changed often, its still higher maintenance frequency than a carbon filter. But it does work very well for small scale grows if you have a properly sized contact chamber.
I've had my share of side by sides with 15,000 volt ballast ozone generators and they did not achieve 100% odor elimination the way the carbon filter did.
Even though the element for an ozone generator doesn't need to be changed often, its still higher maintenance frequency than a carbon filter. But it does work very well for small scale grows if you have a properly sized contact chamber.
Hi!
I rent an apartment, and I got the same stuffs like you. I'm always worried about the smell, cause its not my house, i got neighbours(from hell) and growing is illegal in my country. What you need is : -CAN LITE carbon filter 425m3/h for 1,2 x 1,2 x 2m tent, for this carbon filter you need "480m3/h dospel wk plastics 100" air sucker. This combo should do the trick, there is no smell in my growing room at all.
I rent an apartment, and I got the same stuffs like you. I'm always worried about the smell, cause its not my house, i got neighbours(from hell) and growing is illegal in my country. What you need is : -CAN LITE carbon filter 425m3/h for 1,2 x 1,2 x 2m tent, for this carbon filter you need "480m3/h dospel wk plastics 100" air sucker. This combo should do the trick, there is no smell in my growing room at all.
Tassie1619
Member
You talk absolute garbage mate... I cant even understand what your saying, I have been a commercial grower for 47 years on a massive scale so id disagree with that statement also..
Tassie1619
Member
just because I talk in more understandable terms you just talk in fancy words and hope everyone mistakes you as a master, you knowledge is very limited, and is showing by your attempt to get your point across by confusing the reader peace 
contraptionated
New Member
If you want to debate with me you need to state facts and experiments to back up your claims and at least an explanation. You can't just say your a commercial grower for 47 years . Your confidence is baseless. My suggestions are based on facts not garbage. When you come out saying someone else's statements are garbage without a proper debate you end up being the trash talker.
You can't understand what I'm saying because you're a moron without experience. Also a lier. No way you have 47 years. If you do then you have a learning disability. I have a feeling that you don't even understand that my 10" exhaust/ 6" intake is just an example of a scenario where an intake fan would create positive pressure. I never told him to use any particular size fans. It was to illustrate the reason why an intake fan can cause problems. Everybody else looking at the thread understood it was an example. Perhaps you are so stupid that you couldn't discern my proper English.
if I have passive intake will the smell not leak as I thought I needed neg pressure to avoid smell escaping ? The window in my room will be on half lock I could never leave it open as I'd get burgled lol! So fresh air could be a problem for me really confusing with people disagreeing lol!
contraptionated
New Member
You're the only one who is confused and you keep talking without being able to refute my claim. You are not a worthy opponent for debate. I'm not being mistaken for a master and nobody is making a claim to be a master. I simply illustrated why passive intake is risky and unnecessary in 99% of existing grow rooms. I also cited reference literature (ACCA Manual D) to make you understand how low cfm output of fans will be when the ducting is not dramatically enlarged at the exhaust outlet. All valuable information from my posts and nothing but an overconfident opinion to base your claims. If you're confused, take a little more time to understand the details. I will repeat... You are the only one who is confused. Baseless claims (my claims are not baseless) of overconfident RIU members also serve to confuse others so you would be best to stop posting in this thread until you have enough experience with ventilation to prove your stance by citing recognized authoritative literature. Am I confusing you? That would be a problem with you're reading comprehension level. You're problem, not mine.just because I talk in more understandable terms you just talk in fancy words and hope everyone mistakes you as a master, you knowledge is very limited, and is showing by your attempt to get your point across by confusing the reader peace
contraptionated
New Member
In some rare cases (as I have previously stated in this thread) you may need to use an intake fan. For example: If the sum total of the square inch area of the openings (holes, vents etc) that connect to a fresh air supply are not 4x the area of the exhaust outlet ( ie the diameter of the exhaust fan broken down into square inches) and/or you have no choice to bring in intake air through a long run of duct that includes bends and elbows (which decrease max cfm output of a given diameter of duct) and this restricted intake scenario gives a negative pressure to your room yet it severely limits the amount of air that your exhaust fan can move. In a case with any or all of these factors you will need an intake fan to boost fresh air intake, but you would be careful not to boost it so much that you would supply more air coming in than your exhaust fan can take out.
When using an intake fan, the only way to be sure that you are not creating positive pressure, is to measure the air velocity (with a velocity meter) at the intake inlet and the exhaust outlet. If the inlet velocity is higher than the exhaust (assuming the room is completely sealed except for the air inlet and outlet) , you are definitely creating positive pressure and leaking heat and odors to the surrounding environment. This is bad for a few reasons that I need not explain.
If you do a passive intake with constant exhaust (assuming the room is completely sealed) and you sized the intake inlet and exhaust outlet accordingly, you will always have negative pressure if the exhaust fan is always running.
" Is this confusion? Am I confusing you?"- Oasis; Columbia
Really confused mate cheers tho I don't understand Cfm every thing is too much to take in lol I just gt a 1.2 mtr2 I think I'm goin to need a intake fan with no bends in as I'm goin to need to have my ductin below window to get fresh air in I think if I have passive intake my tent won't get enough fresh air guess it'll work or they'll die lol
contraptionated
New Member
Cfm is cubic feet per minute which can be converted into cubic meters if need be.
No more confusion I understand what you are sayin appreciate it mate