What grain size of activated carbon do you use ? I refilled mine with some and it isn't working well at all. Maybe the grain size is too large??
The Ultimate Odour Control Thread
- Thread starter Arrid
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McStrats
Well-Known Member
I'm a novice grower but I design odor control systems for many industries like plastic extrusion vents where the odors and VOC's are pretty high. Working out your carbon filtration is really just a matter of doing some math. Hopefully some of you will find this useful.
For carbon to work properly the smelly air needs a certain amount of "dwell time" in the carbon. I see a lot of people use fan systems that are too poweful and the air gets pulled too quickly through the carbon. The prices some of you are paying on amazon and other places is high also. Get in touch with these guys http://www.generalcarbon.com/ and ask for a carbon pellet that is formulated for cannabis. Potassium permanganate is another odor absortion media works well. There are literally 100's of different carbon formulas for VOC and odor control.
To work out your cfm needed for 10 air changes per hour you multiply your fan systems cfm x 60 and divide by the volume of the space. For example...if a 4" cent' fan has a cfm rating of 187cfm and your space is 6' x 8' x 8' then 187x60=11,200/384 = 29.1 ach.
So..a 4" fan that does 187 cfm running on full speed with an line carbon filter is pulling too fast and the air is not getting adequate "dwell time"...but that same fan running at 1/2 or 1/3 speed is going to be much more effective.
For carbon to work properly the smelly air needs a certain amount of "dwell time" in the carbon. I see a lot of people use fan systems that are too poweful and the air gets pulled too quickly through the carbon. The prices some of you are paying on amazon and other places is high also. Get in touch with these guys http://www.generalcarbon.com/ and ask for a carbon pellet that is formulated for cannabis. Potassium permanganate is another odor absortion media works well. There are literally 100's of different carbon formulas for VOC and odor control.
To work out your cfm needed for 10 air changes per hour you multiply your fan systems cfm x 60 and divide by the volume of the space. For example...if a 4" cent' fan has a cfm rating of 187cfm and your space is 6' x 8' x 8' then 187x60=11,200/384 = 29.1 ach.
So..a 4" fan that does 187 cfm running on full speed with an line carbon filter is pulling too fast and the air is not getting adequate "dwell time"...but that same fan running at 1/2 or 1/3 speed is going to be much more effective.
I haven't read all of the posts in this thread, too many, BUT, here's what I did: Bought a nice big quality filter and when it was used up, I just drilled out the 3 rivets holding the bottom cover on, emptied it out, and poured in new carbon which I buy in bulk. Put the cover back on, put in 3 new pop rivets and it's good as new! If others are doing this, I'd like to know more about their carbon suppliers. Maybe my supplier isn't the best deal out there 
McStrats
Well-Known Member
http://www.generalcarbon.com/I haven't read all of the posts in this thread, too many, BUT, here's what I did: Bought a nice big quality filter and when it was used up, I just drilled out the 3 rivets holding the bottom cover on, emptied it out, and poured in new carbon which I buy in bulk. Put the cover back on, put in 3 new pop rivets and it's good as new! If others are doing this, I'd like to know more about their carbon suppliers. Maybe my supplier isn't the best deal out there
McStrats
Well-Known Member
I have access to sealed carbon cells in my day gig and I generally grab whatever is surplus. I'm not sure of the granule size but I do know its in the mm's.
john wishmyer
Well-Known Member
ultimate thread on how to get your own place so i cangrow the plant of my dreams
Thanks. What effect does the resistance from the filter have in the calculation? So by my calculation I need about a 9cfm fan for a 2x4x6'11" area. The filter I cannot measure the resistenace, but it's a 4" inlet and 8" length filter and is advertised as a 140cfm filter. If it makes any difference the filter is first in the system and the fan is connected directly to the filter. It seems like only fans low enough are like computer/frideration fans, which makes me kind of skeptical. Thanks!
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McStrats
Well-Known Member
I would run a 4" centrifugal fan with the fan controller on its lowest setting. You may not need a circulating fan as the cfm from the 4" will give all the air movement you need. The carbon filter itself puts up very little resistance, not nearly as much as particulate filtration.
Also, you should be able to separate the fan and filter. My fan is outside of the growing space and the filter is inside.
McStrats
Well-Known Member
What are dims of room and cfm of fan? is it connected to a carbon filter?
HydroEnthused
Active Member
If it wasn’t already addressed, the fan/filter should be situated vertically on the floor with the duct stack pointed straight up no bends. You have no choice but to prefilter room air with MERV 13 or higher so that you don’t limit your carbon life.
I’m running Can125’s for over 9 years because the carbon doesn’t get clogged with dust.
I’m running Can125’s for over 9 years because the carbon doesn’t get clogged with dust.
Randodred
Active Member
I thought filter shloud be up high ?
Please explain..
And your saying my intake needs to be pre filtered..
I was planning on using some carbon frefilters for a boot on the intake from the AC duct..
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HydroEnthused
Active Member
Just use some regular MERV 13 air filters for passive intake and stand up the fan/filter combo a few inches from the floor in case you make a flood. This way your carbon filter doesn’t get clogged with dust. Up high carbon filters are only done if you don’t have the space and I still don’t recommend it.
Randodred
Active Member
Ill be using the fan/filter combo for outtake air ad well..
Using a split room central AC Venting intake into the veg and passive intake from there to the flower.
Outtake air from flower powered by hyperfan 6" with filter also...
So hang it down low to the ground..
Or set it on milk crate??
Still recomend filter fown low..
I will try i suppose i shld have the space
Sent from my LGMS345 using Rollitup mobile app
Using a split room central AC Venting intake into the veg and passive intake from there to the flower.
Outtake air from flower powered by hyperfan 6" with filter also...
So hang it down low to the ground..
Or set it on milk crate??
Still recomend filter fown low..
I will try i suppose i shld have the space
Sent from my LGMS345 using Rollitup mobile app
Randomestguy
Well-Known Member
Anyone have any experience with ipower carbon filters? Looked around and while it's a cheap option a lot say it'll work and do the job maybe die faster, others treat it like a leper. It's already bought so no use crying over spilt milk but I'm hoping it'll work without any leaks or problems, if space and cfm matter for the effectiveness it's a 6"x18" ipower with a 6" green hydrofarm duct fan 440cfm I do have a speed controller if needed and it's for a 5x5x6.5 tent, thanks for any light shed on the matter
Randodred
Active Member
Its what i plan on using.
After hrs of research.
I believe it will work great. And as for life span. I chose the ipower due to the fact it comes apart easily. So can be rifilled.
After every cycle rotate it 90 degrees. And give a cpl taps on the side.
Randomestguy
Well-Known Member
Have you actually used them tho? Jw cuz with ipower it's kinda hit and miss they're a cheap brand and so you can never be too sure but as long as cfm is right I suppose it should be fine. As far as connecting it to the fan it's gonna be intake at the top of the tent would it be fine just sitting on the flange? Like no tape ducting etc cuz the negative pressure would be sealing it against the fan (mostly cuz the fan intake flange is too short to tape ducting or even tape the fan and filter together)
Fishbulb
Well-Known Member
On a 8 big plant run I trust 110% a big as whatever filter I'm rung aka 6" with a ozone generator with a decent exhaust run 6 ft no ssmell it's golden but I grow in a shed in the house I had dehumidifier rocking to keep the carbon filter workering and heat my house 1200 ISA lot of heat that can be used