I look forward to seeing your DIY filter, ganjagoddess. I'm always on the look out for better ways of doing things.
But I'm still skeptical about HOW MUCH better the CTC rated carbon being sold by that ebay seller is versus "average" carbon (whatever "average" carbon might be). You mentioned buying cheap and buying twice. I got twice the carbon for the same price. So even if the carbon I have only offers 50% of the performance then all I'm out is the time it takes to re-charge my filter with the other half of my supply (refurbishing old carbon with heat notwithstanding) or just make the filter twice as big to begin with. But I can't imagine that what I have is 50% worse. 10%? Sure, I'd buy that. 20%, maybe--who's to say? But 50% as effective? No way.
To add more perspective to this debate: Does anyone really know exactly what carbon is used in commercially made filters?
I did some checking....
--
CanFilter makes NO mention as to what type of carbon they use.
CF Group :: Canfan, Canfilter
--I can't find any website or specific information on the
Carbonaire (Eco-Plus) filters other than retailer descriptions about it's "highly activated" carbon content.
--
ProFilter (made by Atmosphere, the Vortex fan folks) describe their carbon as "...TC940 3mm grain sized carbon...". I have no idea what TC940 means. I couldn't find any info about it. 940 is too large to be a CTC number although it is suspiciously in-line with typical iodine rating numbers.
Atmosphere Inc -- High Performance Inline Duct Blowers
--All I could find for
Mountainair filters is from the following "more info" link from a retailer. All I really see there is ad-speak about how their carbon is the best carbon on the planet--no real specifications or test data.
MountainAir Filters - More info
--
General Hydroponics filters (Dutch Breeze) only says in it's PDF brochure that its carbon is 3mm grain size from coal instead of coconut tree fiber. Nothing more.
http://www.bghydro.com/mmbgh/Others/Dutch Breeze Brochure.pdf
--
Phat Filter seems to provide the best tech data on their carbon. And it's a granular carbon with an
iodine rating--not a vapor phase CTC rating.
Phat Filter - Activated Carbon Filters - Technical Data
I went to
Norit (
http://www.norit-americas.com/industry.php), a source manufacture of activated carbon, and searched under....
Industry: Air Purification
Application: Odors
Challenge: Trace organic vapors
....and looked at the four types of carbon listed. The two that specifically list odor removal from gas streams in their product description (Vapure 612 and Vapure 410) both list an iodine number number, not a CTC number.
I'll let each of you to draw your own conclusions about what all that means.
I'm not challenging that the CTC rated carbon sold by that ebay seller is good carbon. But for me, until more/better information influences me, I believe there is LOTS of alternative carbon choices out there that perform similarly for our application--
especially when you include $$ value as a factor. My feeling is that a 10% (or whatever figure is appropriate) increase/decrease in longevity or minimum amount of carbon required to achieve 100% odor elimination, is not a significant concern. And like I mentioned before--I don't distinguish degrees of odor control. It's either 100% effective or it's not. I know that in my attempt at a DIY carbon filter using iodine rating 875+ carbon, it works.
I'm only taking the time to communicate my feelings because I just went through a carbon purchase choice. I specifically debated about whether I should pay the extra money for that CTC carbon on ebay. His advertising makes a compelling case. But I chose carbon from a different ebay seller so I could get more of it and I'm happy with my results.
$0.02
