Questions about extending the life of a carbon air filter.

[jin420]

Hello I had a few questions about carbon air filters and what could be done to make them last longer. I have a 18" carbon air filter with a 6" 435cfm can fan on top of it pulling air through it. I've seen where the sell carbon air filters that are reversible with the advertising saying that if you reverse the filter it'll last twice as long. They say that it only filters through the top half of the filter usually leaving the bottom half unused and to reverse it to get double the lifespan. Does anyone know anything about this or have any ideas on this? Should I try cutting a hole on the bottom of my air filter and sealing the top and give it a try? That or I figure I could wrap a trash bag around the top half to restrict it's flow to the bottom but I'm not sure if that would cause problems with the can fan or not.


Secondly I also read where some people said you can wash carbon air filters with hot soapy water. I'm not too sure about that and don't know if the filters they were talking about are the same kind I'm using. Any ideas about that?


Thanks for any help or input I'll recharge my filter with new carbon when neccessary but I want to make the old stuff last if I can.

 

[BudMarLeY]

first of all once you add water to that filter it will no longer scrub the air properly, as for reversing it, ive never heard about it. but i can assume all the particles that you filtered though in the first place will be getting blown out. the main way to make your filter last longer is to reduce the humidity and keep the filter dry. but thats just my $.02

 

[jin420]

first of all once you add water to that filter it will no longer scrub the air properly, as for reversing it, ive never heard about it. but i can assume all the particles that you filtered though in the first place will be getting blown out. the main way to make your filter last longer is to reduce the humidity and keep the filter dry. but thats just my $.02

Thanks for the advice I definetely won't be washing it then and by reversing it I don't mean I'm gonna go from pulling air through it to blowing air through it. I'm talking about flipping it upside down and pulling air through the other end. The theory is that only the top half of the filter is normally be utilized leaving the bottom half unused. Flipping it upside down should double the lifespan according to this theory. I came up with this idea after seeing an ad in a hydro magazine for a carbon air filter with a design that allows you to do this. I figure I could cut a hole in my old filters bottom and block the top and do exactly the same thing without having to buy a new filter.

 

[mr2shim]

Thanks for the advice I definetely won't be washing it then and by reversing it I don't mean I'm gonna go from pulling air through it to blowing air through it. I'm talking about flipping it upside down and pulling air through the other end. The theory is that only the top half of the filter is normally be utilized leaving the bottom half unused. Flipping it upside down should double the lifespan according to this theory. I came up with this idea after seeing an ad in a hydro magazine for a carbon air filter with a design that allows you to do this. I figure I could cut a hole in my old filters bottom and block the top and do exactly the same thing without having to buy a new filter.

That won't work. The entire filter is utilized, this is noted by the pre-filter becoming darker over time from catching the dust. It's not like they're that expensive to where you have to go through a huge hassle to get it to last a little bit longer and who's to say it will even work.

You will end up spending more in buying activated carbon to fill the filter than you would buying a new filter.

 

[jin420]

If my filter holds more than 10lbs of activated carbon than yeah I'll buy a new one. I can get 10lbs of activated carbon for $30+$10 for shipping on ebay and a new filter is $60. I'll weigh it out when I drain the old carbon out and if it's above 10lbs then I'll buy a new one like you said. I already cut the bottom out before reading your post. It may not work like you said the people selling the reversible filters might just be trying to lie and some fancy expensive filters. Either way I'm about to find out I guess and another thing I just noticed was that my old filter wasn't filled to the top. It had 2" headspace at the top where air could get through freely. I'm gonna wrap some gorilla tape around the bottom(which is now the top) so it has to pull through the activated carbon.

 

[LadyZandra]

Does it have an outer "blanket"?? If so- remove it- and wash it, and air-dry... not in the dryer!
The next step yoluu can do even if it doesn't have an outer blanket-

Go to the Hardware store and get the biggest Arm & Hammer Odor Guard Furnace filter they have (or any brand that says it is for Odors!)
Remove it from the cardboard casing and stretch it out. If it is not big enough to wrap your filter- use 2 or 3 glued or sewn together (use a hot-glue gun! EASY!) Put this UNDER the blanket and bungee them back around the filter - or tie with twine/string...

It will work for 4-5 weeks or so... If your filter is stableized- you can also set an Ona Gel pack or Ona Block inside it-- replace every month...

 

[Kervork]

Heat filter to 500F without oxygen or put a dead skunk in it.

 

[jin420]

Yes LadyZandra it has a pre-filter blanket wrap and I actually washed it with some dishsoap earlier and dried it on a fence in my backyard. I'll definetely try the furnace filter and Ona blocks like you said. I imagine it wasn't pulling through the carbon very much before because of the 2" airgap at the top. I'm gonna set it back up with the gap taped over and see how well it cleans the air.

 

[jin420]

Heat filter to 500F without oxygen or put a dead skunk in it.

The skunk idea is obviously a joke but are you serious about the heat thing? If I took out the carbon I could seal it in a metal pipe and broil it. Don't know if you're just pulling my leg here if not by all means please expound on that idea.

 

[jin420]

I just came across this ehow article on how to recycle activated carbon. It doesn't say anything about a oxygen free environment and says flammable vapors are emitted so I would need to use a electric oven. Knowing that me thinks sealing it in a pipe could create a pipe bomb no? http://www.ehow.com/how_7411828_recycle-activated-charcoal.html

 

[jin420]

Here's a different ehow article with a different process described in it. The other article said to boil then bake and this one says just to bake. Any thoughts? http://www.ehow.com/how_5808727_reuse-activated-charcoal.html

 

[mr2shim]

That ehow article is stupid. You can't reactivate carbon at 300 degrees. That shit is heated to insane temperatures in commercial reactivation. Your stupid oven at home won't do anything.

https://en.wikipedia.org/wiki/Activated_carbon#Reactivation_and_regeneration

Do you really think there would be multi million dollar plants around the world specifically for the reactivation of carbon if you could just do it at home in an hour?

 

[jin420]

If that's the case then I'll scratch that idea off. Gonna see how many pounds my filter holds and decide if it's cheaper to refill(10lbs-$40) or get a new one($60).

 

[jin420]

Just found out my filter holds just under 8lbs of carbon so yeah it's going to be way cheaper to refill it myself. And I do mean way cheaper I can get 25lbs of carbon for $90 while a new filter is around $60. With 25lbs being enough to fill it 3 times then I'm looking at a 50% cost savings here and yes I know how to fill them right. All you need to do is tap all around it with a rubber mallet to make sure there are no voids and you're good to go. Plus the one I bought originally has a 2" gap at the top where it wasn't filled all the way and I know I can do a better job than that.

 

[jrainman]

That ehow article is stupid. You can't reactivate carbon at 300 degrees. That shit is heated to insane temperatures in commercial reactivation. Your stupid oven at home won't do anything.

https://en.wikipedia.org/wiki/Activated_carbon#Reactivation_and_regeneration

Do you really think there would be multi million dollar plants around the world specifically for the reactivation of carbon if you could just do it at home in an hour?

Agree and the heat source that is used to activate the carbon is 2000 deg steam ,it opens the pours in the carbon this process (activated carbon) is what makes it absorb

 

[rocknratm]

I say buy an oversized one and pull way less than the rec cfm through it. I had a 8" that lasted over 2 years because it had a weak fan on it for a while. Less air through longer it lasts, so go from your 4" to a 6 if you can. but they are spendy as hell

 

[joe macclennan]

You will end up spending more in buying activated carbon to fill the filter than you would buying a new filter.

Not necessarily true. I have both bought and built filters. Up until recently you could build a way better filter than you could buy for substantially less. The filters I built have two inches of carbon vs. the one inch you get with most store bought brands.

gotham is selling filters now w/two inches of carbon. They are very reasonably priced.http://www.ebay.com/itm/8-x-42-INCH-ACTIVATED-CARBON-CHARCOAL-AIR-FILTER-ODOR-CONTROL-SCRUBBER-F014-/290631669670?pt=LH_DefaultDomain_0&hash=item43aaff57a6

At this price it is not worth building one.IMO. My filters took a little more than an hour to put together each, and to be honest were kind of a pain in the ass. They do have way more surface area than most store bought filters though. I used 1/2 inch hardware cloth for strength with aluminum screen for screen windows hot glued to it to hold the carbon in. All in I had less than 150buks in a 8 inch x 36inch filter w/2inches of carbon. One this size takes close to 50 lbs of carbon. My local hydro store wants over three hundred buks for a comparable one.The best deal I have found on activated carbon. http://www.ebay.com/itm/55-LBS-Bulk-Premier-Activated-Carbon-4-Aquarium-Koi-Fish-Pond-Reef-Tank-Filter-/160821358478?pt=LH_DefaultDomain_0&hash=item2571b32f8e

 

[jin420]

I say buy an oversized one and pull way less than the rec cfm through it. I had a 8" that lasted over 2 years because it had a weak fan on it for a while. Less air through longer it lasts, so go from your 4" to a 6 if you can. but they are spendy as hell

I do have a 6" filter right now it has a 435cfm 6" cap valuline fan sitting on top of it running wide open. I wish I could throttle it down but it is one of 3 centrifugal fans providing airflow between the three grow chambers that cover most of my bedroom. The fan exhausting out of my closet grow chamber is only pulling a hundred something cfm's so after my 420 harvest which is currently flowering in there I'll redesign that chamber so that it's in there attached to a weaker fan. After wrapping a garbage bag around the top 4" to solve the gap problem I had(they didn't fill it to the top) and flipping it upside down it's actually doing a pretty good job now. I used to be able to smell my grow after walking in the front door of my house after work and now I only smell it when I get right to my bedroom door. I'm gonna seal my door soon to where I have my room airtight so after I do that and maybe get another filter I think I'll be in buisness.

 

[jin420]

Not necessarily true. I have both bought and built filters. Up until recently you could build a way better filter than you could buy for substantially less. The filters I built have two inches of carbon vs. the one inch you get with most store bought brands.

gotham is selling filters now w/two inches of carbon. They are very reasonably priced.http://www.ebay.com/itm/8-x-42-INCH-ACTIVATED-CARBON-CHARCOAL-AIR-FILTER-ODOR-CONTROL-SCRUBBER-F014-/290631669670?pt=LH_DefaultDomain_0&hash=item43aaff57a6

At this price it is not worth building one.IMO. My filters took a little more than an hour to put together each, and to be honest were kind of a pain in the ass. They do have way more surface area than most store bought filters though. I used 1/2 inch hardware cloth for strength with aluminum screen for screen windows hot glued to it to hold the carbon in. All in I had less than 150buks in a 8 inch x 36inch filter w/2inches of carbon. One this size takes close to 50 lbs of carbon. My local hydro store wants over three hundred buks for a comparable one.The best deal I have found on activated carbon. http://www.ebay.com/itm/55-LBS-Bulk-Premier-Activated-Carbon-4-Aquarium-Koi-Fish-Pond-Reef-Tank-Filter-/160821358478?pt=LH_DefaultDomain_0&hash=item2571b32f8e

Appreciate the insight man but I'm a broke diy'er I'm probably gonna have to buy the carbon and do it myself. So do you think increasing the thickness really helps out a lot? I might be able to split my old filter in half with a dremel, extend the outer shells out and graft some material in to fill the gaps and increase the thickness of my filter. What do you think about that idea? And is that ebay listing for the 55lbs of carbon the same kind of carbon air filters use? I ask because I've heard of some carbon being described as air phase and other as liquid phase and wasn't sure if they were interchangeable. But yeah man if that's the same stuff then I'll definetely be ordering some thanks for the link.

 

[SimonD]

At the risk of stating the obvious, air always flows via the path of least resistance. When using a larger filter and a smaller fan, assuming we're pushing through the filter (you can prorate this for pulling), air will first exit through the holes closest to the flow. As those opening are closed by the debris, or a bigger fan comes into play, air moves to the next available opening and so on. Lining the scrubber's interior with a filter will extend its life, again, when pushing. Most DIY stores sell a filter kit that includes a plastic grate of sorts. It snaps into place and it's perfect for holding the material in place against the round interior of the scrubber. With all this in mind, one is better off investing in the biggest filter he can support. It will last longer and work better. FWIW, I've used and grown with virtually every model in the Can line. Good luck.

Simon