I made my own carbon filter which seems to work pretty good so i figured I'd share it. Its nothing fancy, and I'm sure there are others pretty much just like it. So my apologies for being unoriginal. But i just cant see spending a hundred bucks for something as simple as a carbon air filter.
This one cost me about 25 bucks to make. And $20 of that was the carbon i bought, which I'm sure you can get for less than i paid at the pet store.
Here's what i used.
1- Premium Grade Filter Carbon. I got a 2 quart container at the pet store. Cost 20$.
2- A cut-to-size mesh furnace filter. $5 at home depot. They have different sizes. The one i got started out about 2ftX3ft and 1 inch thick.
3- A cardboard box.
4- Some packaging tape.

If you are going to use this or any other carbon filter you need a powerful enough fan to move enough air to make it work. I use a 6in. centrifugal inline fan rated at about 450 CFM. I have the fan inside a 2x4x5 tent connected to a DIY cool tube. The carbon filter is outside the tent, sitting on top of it above a 6in vent hole.

Since i use a 6 in fan, i decided to use a slightly larger filter. I made a 8in. X 8in. box. (depth undecided at this point). I cut a 6 in. round hole in the bottom. My fan goes directly into this 6in hole from inside the tent. I cut the 2ftx3ft furnace filter into 8x8 squares (like the one in the pic above).
I put one square in the bottom of the box (covering the 6 in round hole for the fan). Then i poured a layer of carbon into the box and spread it around ontop the filter. Then i put another square in and put more carbon on it. I completely covered the surface of each layer with carbon. I did this for about 10 layers, and used about 2/3 of the carbon i had bought.
My original plan called for a piece of window screen to be placed in between each layer to keep the carbon from falling all the way to the bottom of the filter. But the carbon i got is coarse enough it does not fall though the furnace filter material i got, so i didn't need the screen. If you use a coarser filter material and/or finer carbon you should get some screen.
Basically thats it. You can make it as big or small as you want. The deeper it is (more layers) the better odor filtering you will get. But more layers will require more CFM's. My 450 CFM fan blows PLENTY of air through this filter. I could probably put several more layers into the filter and still be moving enough air to cool my tent.
This filter does NOT take out ALL the smell. But it helps very much. I also use Ona Pro Gel.
So i hope i described this in a way you can understand. I'll gladly answer any questions you have about it. And feel free to criticize my design or recommend improvements.

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I asked the gang what did they think?

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Thanks Roseman. That means a lot coming from you. I put this up just to show a friend of mine what I did, but I've been looking at other ones on here, and I think that mine is more effective and easier to make than many of them. So i'm just going to throw this back out there. Happy growing everyone!

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+rep man. lol just cause im the dude that spent $120 on a carbon filter.....



p.s. thanks for sharing!

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This is a great thread!

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Thanks Damnbigbuds, and happy growing.
I have since purchased a 'Speedster' fan speed controller. Temps are much cooler now and i dont need the fan running full blast to cool the tent. The reduced fan speed actually makes the filter work better! I suppose any carbon air filter has a specific CFM at which it is most effective.
Fully reversable!
I also recently took the filter off and turned it over (upside down). This stirred up the carbon a bit and now the air is coming from a different direction and the filtering should be even better.

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nice diy carbon filter... I'm planning on making my own pretty soon.. so im doing all my research before i start making one.. my budget is probably around 40 dollars

sorry for any dumb questions but im a newbie doing a lot of homework before i plunge into bubbleponics (roseman is my mentor) lol im gonna grow one single plant in a 3ftx 4ft closet should i use a a carbon filter or would ONA be sufficeint for odor control thaxs for your help

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It depends on how "stealthy" you need to be. If you want 100% protection I would recommend both the filter and the Ona.
The smell will come on slowly as the plant gets bigger. Start with one (the filter or the Ona) and if its not good enough for you, add the 2nd method. Some plants smell a lot more than others.

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