help me with carbon filter

Discussion in 'First Time Marijuana Growers' started by abrahamx, Oct 1, 2010.

  1. I have 7 plants vegging right now. See my grow journal if interested entitled "first serious grow" Been vegging for about 5-6 weeks now and am just waiting a few more days to recover from a transplant before switching to 12/12 and putting up the 600watter. I know they are going to smell so I am starting to consider a carbon scrubber. I have read up on all the dyi's etc... What I am really wanting is for someone experienced advise me as to how much scrubber I will need. It is a grow downstairs and I am figuring only 4 or so will be females. I am wondering if one of these small ones will do the job or not. I have no dedicated exhause so I was thinking of just having one free standing. My wife smokes but does not know I am growing the plants. When/if she finds out it wont really be a big deal, but she will not want to smell them as we do have family over and that could be an issue. Please let me know what would be the best way to go under these circumstances. thanks for any help.
  2. You match the cfm rating to the cfm rating of premade carbon filter. Take the demensions and build your own from the diy section
  3. I'm kinda of wondering of how much cfm I would need in my situation. I know what you are saying but I am not sure of how much or little I would need to get the job done. Other people who have grown in similar situations would be able to tell me. I know I can just do the trial and error myself but was looking for some one with experience to assist.
  4. i too am trying to figure out how many cfm i need to push enough air out of a scrubber. i was thinking 90 cfm might work for a pc grow
  5. figuring it out is not nearly as hard as it might seem :) to measure the volume of your grow space in cubic feet, first measure the length, from one wall to the opposite wall. then measure the width, which (assuming your room has four walls :rolleyes:) would be the distance from the OTHER wall to its opposite wall. finally, measure the height, floor to ceiling. of course, you're going to need all the measurements to be in feet. it doesn't have to be terrible precise, like say your height is 7 feet 3 inches you could just call it 7 feet even, etc.

    once you have your measurements for Length, Width, and Height, multiply them all together. the product will be the number of cubic feet in your grow space. for instance, if your room has length 12 feet, width 10 feet, and height 7 feet, 12*10*7 = 840 cubic feet.

    now that you have that measurement, you're going to want a fan with a CFM (cubic feet per minute) rating that can exchange 840 cubic feet of air in at least 5 minutes, so take the volume of the room (my hypothetical room is 840 cubic feet) and divide it be 5. 840 cubic feet per minute/5 minutes = 168 CFM, so for my hypothetical room i would be just barely getting by with a 170 CFM inline fan. if the person growing in this room wanted to play it safe, which is what i recommend, they would use 200+ CFM just to be on the safe side, or use two 170 CFM fans, one on either side of the room, which might actually be more effective.

    one last thing.. there are plenty of DIY carbon filter plans on this site, and i'm sure they all work, but for my money i think it's worth it to just go ahead and buy one that was designed for exactly this purpose. i mean, you might save $30-$50 bucks, but if you miss the mark on one tiny thing you've pretty much wasted the money you did spend on it. there are some really good deals out there with inline fan/filter combos. high tech garden supply had the best deal going when i got mine, so you might want to start there. hope this helps!
  6. #6 Tihspeed, Oct 3, 2010
    Last edited by a moderator: Oct 4, 2010
    You multiply times five. Your looking to remove the total air space three to five times a minute. Not every five minutes

    debaitable. But overkill is nice because it makes for a quiet fan when slowed down

  7. thanks ti! i've always heard every five minutes, or maybe i just misunderstood. but 5 times a minute is definitely the way to go if you can! it illustrates a point worth mentioning, and that is that a lot of people (not necessarily the guy who started this thread, just in general) ask on forums here "what is the minimum i can get away with?" but that's faulty logic. if you're going to do something like grow cannabis, and you're trying to do it right, shooting for a "bare minimum" is the wrong way to go.
  8. if you multiplied by 5 you would need a 4200 cfm fan. You still divide, you just divide by the amount of minutes in which you want the air exchanged in the room. ie. 840/1 =840cfm fan 840/2 =420 cfm. I would with about every 2 mins. So use something like a 6" tjerlund inline fan 500cfm and your set. Also all this is useless without a proper carbon scrubber. Don't waste money trying to build one. The only ones that truly live up to their advertisements are mountain air. You can get a cheaper one but it wont work as well.
  9. yeah i know... if you skimp your plants don't have enough fresh air and if you go big you can always slow it down to make it quiet.. sounds like a no brainer.. why be cheap

    nope i had it right... Like i said... debatable.... The air should be removed three times a minute minimum... most say five times a minute... I split the difference... and just say three, but if you add a carbon filter i multiply that number by two... so it balances out

    there are alot of other factors to add in as well...basement grow, ambient air temp.. ac in the room, carbon filter, size of the fan or fans... does your light have its own fan just to cool the light... tons and tons of stuff..... just as an example.. ambient air temp where i live is normally 115 outside... no way i can grow outside... and forget about the garage

    If you wanna cool a huge room down once every two minutes thats on you... not what i would recommend..... not looking to get into a war with anybody... I would look at alot of other posts by people saying their grows are too hot and don't understand why

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