# questions regarding welding grade Co2



## pepperonihead (Nov 25, 2004)

When I first started my planted tank I bought my Co2 canister from Air Gas in Long Beach, Ca. I used their Co2 with no ill effects to my fish, and my plants grew out of control as usual! I moved and started using the Co2 from the LFS because I heard you should only use Beverage grade Co2. Well I am sick of paying higher prices and would much rather only pay $10 so I am thinking about going back to the Air Gas to get my Co2. Is it really necessary to use medical or beverage grade Co2?


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## Paul S (Jul 13, 2005)

Welding shop or places that refill fire extinguishers are your most economical choices IMHO

PS


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## Salt (Apr 5, 2005)

On some forums posters get ridiculed and their threads get locked for even bringing this up. It seems quality / grade concerns are a very sensitive issue to a lot of people.

My own experience is it's not a big deal what grade CO2 you use. However, I also don't think it's a big deal if you choose to pay for a higher grade of CO2. Personally, I get my CO2 from a welding shop, because that's the only place I can get CO2 where I live.


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## MatPat (Mar 22, 2004)

I have always purchased CO2 from a welding shop and have yet to have any problems. Who knows, maybe I would notice my plants growing better if I were to use "food grade" CO2, but I seriously doubt it. They already grow faster than I like so an increase in growth by using "pure" CO2 is not something I would be interested in.


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## pepperonihead (Nov 25, 2004)

*Thank you all very much*

LOL, I didn't notice it until I pulled my empty canister but guess where my empty canister came from!? You guessed it! AIR GAS! My LFS is charging $18 for welding grade Co2. So I just went to Air Gas and got a full one for ten bucks! Live and Learn!


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## BryceM (Nov 6, 2005)

How many places do you think make CO2 for bottling? My guess is maybe 2 on each coast. My guess is that no matter how it's labeled it all came from the same place. Its not like there's a huge market for varying grades. Industrial CO2 is produced in a pure state anyway.

I did read one post about someone who had got nitrogen instead of CO2 in his cylinder at refill time. Didn't really help the plants all that much......


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## JerseyScape (Nov 18, 2005)

My Co2 is from a welding shop. I paid 68 dollars for a FILLED 5lbs bottle.


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## JaySilverman (Jun 19, 2005)

I get mine from a beer and wine brewing store. I have no idea the grade of my CO2.


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## riojohn (Dec 9, 2009)

HI,

Welding grade CO2 is a general purpose shielding gas for steel sections and plate. Used primarily for short arc welding of mild steels with all diameters of solid steel MIG wire and fluxcored gas shielded wires

CO2 is stored as a liquid under pressure, and during the process of transferring it from one container, such as a delivery truck, to another container, such as a dealer's container, it gets extremely cold. Any water or mix of water and other stuff would freeze to ice during that process. Then, when the CO2 warmed up, that water would float on top of the CO2, but I believe the CO2 taken from the bottom of the dealer's tank, not the top. So, I doubt that you would get water soluble contaminants in any CO2 from any source. In any case I haven't heard of anyone having problems with contaminants in CO2, no matter what grade they use.


Thank you....


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## jestep (Nov 14, 2009)

BryceM said:


> How many places do you think make CO2 for bottling? My guess is maybe 2 on each coast. My guess is that no matter how it's labeled it all came from the same place. Its not like there's a huge market for varying grades. Industrial CO2 is produced in a pure state anyway.
> 
> I did read one post about someone who had got nitrogen instead of CO2 in his cylinder at refill time. Didn't really help the plants all that much......


I have to agree. I get mine from a brewery supply store. From what I've researched, CO2 doesn't have grades like compressed air or other breathable gasses. The grading industrial vs. food are actually the grade of the bottle, where food grade bottles are glass or ceramic lined to prevent any aluminum or other contaminants from seeping into the liquid co2. There may be a 3rd nuclear grade or something similar, but none of us would need anything like that. I would say as long as the place is a reputable establishment, you're probably fine using it.

On the nitrogen topic, this sounds fairly dangerous, since CO2 is liquid in the bottle, and nitrogen is usually in a compressed gaseous form. This would quickly exceed the pressure rating of a CO2 bottle, if the person was trying to fill to 3000 or 4500psi which are the most common compressed gas pressures. CO2 tanks are rated at less than 2000psi normally. Anyway, I would avoid that filler!


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## mgamer20o0 (Jul 15, 2006)

oh i am so glad i clicked this one Mr. pepperonihead......

really dont think it matters what kind of co2 you get.


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## Newt (Apr 1, 2004)

< 0.1% impurities

http://fins.actwin.com/aquatic-plants/month.9611/msg00025.html


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## freshyleif (Jan 9, 2008)

The welding shop that I refill at said that the CO2 that I get is the same as the CO2 that they sell to most of the local winery's. He said that it was the same as food grade and that if I wanted a more pure CO2 it would cost $125 for a 5g refill and that it is really only used for lab purposes. He also said what Newt posted that the impurities in what I get is less than 1%.


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## snail_chen (Dec 4, 2009)

Mine is from a wedling store. However, my plants initially did very well then the ecosystem collapsed?


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