DIY Carbon Filter. Epic Fail...

A few quick details : Home made grow tent, 3'x2'x5'. 2 bag seed plants under an array of different spectrum CFL's. Week 7 Veg (5 days until flower). My 'ladies' are doing great so far. I just completed construction of my grow tent and I couldn't have been more thrilled to move them into their new home today in preparation of the flowering cycle to come.

I used this tek for a DIY Carbon Filter, https://www.rollitup.org/do-yourself/101248-best-diy-ez-walmart-carbon.html which in itself worked great, but.... When I put my girls in I noticed shortly after I could still smell them outside of the tent. I believe my problem is that the fan I'm using for exhaust is just a 8" table top electric which I jery rigged to a sheet of plywood in the ceiling of the tent. I can feel some air coming through the filter but not much and when I put my hand to the suck side of the fan I can feel air blowing back into the tent. Obviously there's too much resistance from the filter and my lil' honeywell just doesn't have the balls to push the air through.

Is there anything anyone can think of that I can do short of buying a 4" inline duct fan? I have to say I'm fairly disappointed with the way things are now and I've almost blown my budget building the tent. Any ideas from fellow DIY'ers would be greatly appreciated, Thanks guys.

Puff.

Most of the DIY is garbage, set it up right with reliable gear to avoid any problems. Plan before you plant. Sorry if I come off as a dick. No disrespect.

You can use a $13 bath fan from lowes (50 cfm 4 sones) with a 3" outlet. Amazon sells the BFQ90 for $35 shipped (90 cfm 2.5 sones). It has a 4" outlet.

Bath fans are designed to handle a bit of static pressure and will pull air through a thicker carbon layer than duct booster fans.

Inline duct fans are so cheap these days you can purchase them for the price of a couple of packs of ciggies.

If minimising cost is an issue I would look on the second-hand pages of my local classifieds. Many growers give up before even starting through circumstance. JMO.

Oh that aquarium carbon is not very good for air filters (I have 10 pounds of it sitting around after learning that lesson). You can get coconut carbon on eBay by the pound. That will make a HUGE difference.

Moebius said:

Inline duct fans are so cheap these days you can purchase them for the price of a couple of packs of ciggies.

If minimising cost is an issue I would look on the second-hand pages of my local classifieds. Many growers give up before even starting through circumstance. JMO.

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I've looked around for something reasonably priced and the cheapest I can come up with is like over $100, those are some expensive cigs my brutha! Could you recommend a model or a place to look? Aside from the aforementioned classifieds lol..

PuffinChronic said:

I've looked around for something reasonably priced and the cheapest I can come up with is like over $100, those are some expensive cigs my brutha! Could you recommend a model or a place to look? Aside from the aforementioned classifieds lol..

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LOL ... of course, youre not in a country that taxes the shit outta ciggies.

All the same $100 dollars seems expensive for even a new 4" inline. ... a quick look on ebay.com (U.S) and there are a couple brand new/boxed on buy-it-now for less than $60

http://www.ebay.com/itm/Master-Flow-4-6-8-inch-INLINE-DUCT-FAN-blower-HIGH-CFM-cool-vent-exhaust-/330803399426?pt=LH_DefaultDomain_0&var=&hash=item4d056b4b02

edit:
this one is even cheaper less than $30.. http://www.ebay.com/itm/100CFM-Exhaust-Blower-4-Inline-Duct-Booster-Fan-4-Inch-Cooling-Vent-Hydroponics-/180992378302?pt=LH_DefaultDomain_0&hash=item2a23fc85be

With a filter that size (pencil cup) a $100 inline fan (200-400 cfm) will move the air through too fast. In order for the carbon to do its job it needs a certain amount of contact time. Even the 50cfm bath fan might be too much.

Maybe the 4" duct booster would be best after all. It claims 80 cfm but it is not designed for static pressure so the CFM will drop drastically pulling through the room and carbon.

SupraSPL said:

With a filter that size (pencil cup) a $100 inline fan (200-400 cfm) will move the air through too fast. In order for the carbon to do its job it needs a certain amount of contact time. Even the 50cfm bath fan might be too much.

Maybe the 4" duct booster would be best after all. It claims 80 cfm but it is not designed for static pressure so the CFM will drop drastically pulling through the room and carbon.

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Well I didn't follow the tek to the letter, the "pencil cup" I used is pretty large but I think your right about not enough contact time as the air passes through the carbon if I were to go the bathroom fan route. also the tent is in my bedroom so quiet is the key or the old lady will throw a fit. lol

http://www.homehardware.ca/en/rec/index.htm/Heating-Ventilation-Cooling-Home-Comfort/Heating/Furnace-Parts-Acc/Accessories/5-Booster-Duct-Fan/_/N-2pqfZ67l/Ne-67n/Ntk-All_EN/R-I5532211?Ntt=duct+fan

Sweetness... I'm hoping that something like this will do the job. thanks for your help guys!

Puff.