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Odour problem!! What Size Carbon Filter do I need??

Discussion in 'Grow Room Design & Setup' started by matt7835706, Jan 30, 2012.


    matt7835706 Well-Known Member

    I have a 5 x 5 x 8 room (sealed) with six large plants and the whole house smells.

    Can someone please tell me what size carbon filter to use. I just want it to recirculate the room are to purify it and reduce smell, will this affect humidity and co2 levels? I need to get down to zero smell and want to get what it takes to do the job right!!

    I have been thinking about this unit on ebay http://www.ebay.ca/itm/6-ACTIVATED-...955?pt=LH_DefaultDomain_0&hash=item5d30eb238b Will it do the job?


    lilrich11 Active Member


    I bought the 4" version, my plants havent started stinking yet. But it kills the smell of the yeist in the bottle
    This ones better then the one your looking at. You can also upgrade with a new filter on the intake end and put that one on the exhaust end.
    Double fitler the air, better chance of killing all that odor. You can throw a jug of ona beside the exhaust to help scent killing

    skunkd0c Well-Known Member

    i would go for a 8inch inline fan preferably with suitable filter
    if that is too big a 6inch, will be ok, try to get the turbo version
    do not even consider a 4inch fan, they are very inefficient compared to the larger fans

    Catchin22 Well-Known Member

    Good combo in my sig. Should clear the room once every 5 minutes or less so you're going to have to calculate that yourself using the square ft and CFM rating.

    shrxhky420 Well-Known Member

    Read this

    To control excessive heat build-up a ventilation system must be incorporated. This can be done simply with fans, or a
    carbon filter/fan combination that will clear odor and sterilize the area at the same time. Ideal Grow Room temperatures should be between 65*F and 75*F. If temperatures rise above 85*F your plants will begin to suffer from excessive transpiration, which is the loss of crucial water held within the leaves and stem cell walls. Another factor that ventilation will help control is the relative humidity level or RH of your growing environment. RH can also have an affect on transpiration. Proper humidity levels range from 45%-65% RH. A Thermometer/Hygrometer is a must to maintain proper levels. Some General Tips:
    Lighting systems generally consist of four components: ballast, cord and socket, bulb and reflector. A 400 watt lightwill cover a 3x3 or 4x4 area, a 600 watt will cover a 4x4 or 5x5 area, and a 1000 watt can usually cover up to an 8x8. Remember the more light you have, the more the plants can feed, thus photosynthesize and produce a fruitful yield.
    • When air cooling lights, use at least 250 cfm per 1000 watts. (I THINK THIS SHOULD BE CLOSER TO 400CFM TO COOL LIGHT, just my opinion)
    • Generally it’s a good idea to use 3000 btu of cooling energy per 1000 watts.
    • Typically, you will want to exchange the air in your grow room every five minutes. To figure this out use the formula Length x Width x Height = Cubic Ft, then Divide by 5 to get your recommended CFM (Cubic Feet per Minute)
    (Example 8ft x 12ft x 8ft = 768 divided by 5 = 153.6 so you would need at least a 153 cfm fan to exhaust your room)

    Using Carbon Filters:
    Carbon filters are great to use in your grow room. Since you need an air exchange any way, why not sanitize your room in the process? Match the CFM of the filter and fan, attach it to fan intake, and you are ready to go. All carbon filters have a recommended CFM; it is important not to exceed the recommended CFM as the filter will not sterilize the air properly. When mounting your carbon filter it is best to mount the filter high in the grow room to allow any hot air to be filtered first. If mounted and connected properly your fan and filter will accomplish three things:

    • Act as an air exchange in your grow room
    • Decrease the temperature by taking out hot air
    • Sterilize grow room killing mold spores, pathogens, and deodorizing

    Hope this helps!!! Stay HIGH!!!

    shrxhky420 Well-Known Member

    By the way I wouldn't go with the fan filter combo you chose, I would get a fan and filter combo like this one fan filter combo.jpg

    I've heard that you don't want to refill filters on your own, as you can leave big gaps of air rendering the filter useless. Factory packed and sealed filters are the way to go.

    so filter--> duct-->fan-->duct-->light--->duct out. or you can swith fan and light position, everyone has a preference. stay high

    Catchin22 Well-Known Member

    Who wrote that info on the CFM for carbon filters? I've heard a completely different thought on it that CFM for the fan if anything should be higher in order to "slam" the air into the carbon. That running at slower speeds does not increase filtration but instead impacts it negatively.

    2supra4u Well-Known Member

    ^ if you try to force more air through than what the filter can accept, you decrease air/carbon contact time which can result in smells getting through.

    Matt, just get a 4 inch or 6 inch fan/filter combo rated for 200cfm and set it in the corner and be done with it if thats how you want to do it.
    Get a fan speed controller if its too noisy, or just put on some duct to blow air out at a different spot then where the filter is.

    your room is 200 cubic feet. as long as your scrubbing near your room volume every minute, you should be fine.

    SFguy Well-Known Member

    agred w/2supra, i have a 36x12 inch scrubber that i hook up during flower it work great w/ a 6" vortex, and im exausting out 2x600s and a1000w with it, cherry

    Catchin22 Well-Known Member

    I understand that "logic" in thinking but do not believe it's actually true. Faster air circulation slams the air molecules into the carbons surface while increasing surface tension and breaking air layers. Thus more contact with the carbon and a faster recirculation rate.

    shrxhky420 Well-Known Member

    I got my info from doing a lot of research, this was one of the pages I found and thought that the info was good and accurate. Would you fill your gas tank up with 92 octane knowing it can't burn it properly and that you should only be putting in 87?

    here is more info I found interesting.

    The carbon filters will remove 99% of odors in the room if the temperature, humidity and the CFM of the outake fan is met. The carbon filters can operate at a maximum temperature of 80 degrees centigrade and up to 70% humidity. A properly running grow room will be well within these limits. In order to find the proper can filter for your room, you simply calculate the cubic feet of the room and divide that by the number of minutes you would like to exchange your air (2 minutes is good). That will be the minimum CFM of your fan. The CFM number should be higher than the exhaust minimum of the filter itself. This way any CFM loss from the filter is covered. Periodic cleaning of the pre filter will also keep things flowing and is the only maintenance. The carbon filters can technically be refilled but this would be futile. The filters are packed with industrial shakers and the carbon becomes packed evenly with no gaps for air or smell to sneak through. You would not be able to achieve this. The life of the carbon filter depends on the concentration of the smell, humidity and how much volume of air is flowing through the room daily. You can expect 18 or so months of service from a properly run filter. You can push or pull air through a filter but pull is best as the surface area of the carbon is utilized the most efficiently. If you do happen to push air through you should take the pre filter off for better air flow. With over a dozen filters to choose from and CFM parameters clearly marked on the containers, carbon filters are a viable means of odor removal.

    Carbon filters have to cfm ratings, min and max. say 200-400cfm. so a fan with 145cfm is not adequate enough to work this filter and a fan with 500cfm would be too big. Stay high!!!

    2supra4u Well-Known Member

    its not logic, but fact.

    "slamming" may make circulation in the sealed room faster, but all its doing is lowering the efficiency of the filter. Basically you making the filter clean the air twice, cuz the first time it goes through not all of it is being scrubbed.
    so you might as well do it the way it should be so that when air goes thru it is scrubbed fully the first time.

    Catchin22 Well-Known Member

    Fluid dynamics seems to say otherwise, but I wont argue it. :)

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