# 10, 15, or 20 lbs CO2 tank?



## NWA-Planted (Aug 27, 2011)

green_valley said:


> I am getting ready for my pressurized CO2 system that should be here this week. I was wondering which I should go with 10, 15 or 20 lbs. I guess the bigger the longer it will last. How long will they last ? What other advantages? Also, how tall is 20lbs tank?
> 
> This will be for my 50 gallons (long), 48x18x14. What would you suggest for the bubble per second?
> 
> Thank you


On a 50, heck a 5 pound should last roughly a few months. I saw a thread on a 20 pound and it lasted someone close to a year.

Just depends on your tank, the BPS will depend too, I really dont go by a BPS I have my output in check with my drop checker. Just have to take a day and get it dialed in right so you avoid gassing any fish. Its also going to depend on your diffusion, I am running mine through a cermic disk into a powerhead and I am probably not even using a buble count higher then 3-4 bps and thats on a 125 gallon tank


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## KrazyFish (Dec 23, 2010)

You should the biggest one you can afford. Keeping in mind your space limitations also.


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## fresh.salty (Jul 2, 2010)

I doubt a 20# will fit under the stand. I have a 10# on my 90g and it's a tight fit with the regulator. I get about 3-4 months from the cylinder, but my fish hate me.


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## green_valley (Sep 14, 2011)

Thank you for the response everyone. Yeah, my stand is a short stand anyways, so it will be outside and behind the stand.


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## EntoCraig (Jun 7, 2010)

My 53 gallon tank has a 20 pounder and it lasts about 6 months. Im cranking some serious co2 though. 

I use a drop checker instead of the bpm and I diffuse with an inline diffuser.

Hope that helps.


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## Craigthor (Sep 9, 2007)

I would do a 20# if you have the room. Here it only cost me $7 more to fill a 20# tank over a 5# tank.

Craig


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## [email protected] (Jul 17, 2008)

green_valley said:


> I am getting ready for my pressurized CO2 system that should be here this week. I was wondering which I should go with 10, 15 or 20 lbs.


Purchase the largest tank you can find space for - and return for a swap. I had a 50# tank that I traded in on a 20# tank as I couldn't easily get the 50#er down the stairs to the basement where my tank are. There may be 35# tanks available too. 

I had a nice shiny 10#er that I swaped as it had to be filled at a different location than where I swap tanks. Too much trouble going to two places.


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## galabar (Oct 19, 2011)

How much does a 20# full cylinder weigh?


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## proaudio55 (Oct 20, 2011)

@ galabar, a full 20lb aluminum CO2 tank weighs about 45lbs. 

As for cylinder capacity, I would encourage anyone to go with the biggest tank they can fit and afford. I don't think anyone has ever said "gee, I really wish I could go to the welding center more often; I want to fill this blasted CO2 tank but it just seems to run forever"

And yes, I've had my 20 pounder for over a year now on the original fill. Obviously that is related to: 
#1 good seals on the valve stem and regulator setup. 
#2 a relatively slow bubble rate.


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## DeusExCalibur (Dec 1, 2011)

My steel 20 lb. tank is roughly 27" tall


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## discusonly (Mar 28, 2010)

I started out with a 5lbs for my 90 gal tank. It lasted a few months so I went and got it refilled. As a walked out the door, I learned that a 20lbs refilled was only a few dollars more so I traded my tank for a 20lbs. I say if you have the space, just go with the more standard size for welding shop (20lbs). 

The 20lbs tank is quite big but since I have a tall Oceanic stand, it's not an issue. Just your the height of your stand first.


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## Leaky Filter (Nov 30, 2011)

I'm working with a power seller on the forum to make up a two stage rig. My stand is 27" from floor to top.

It looks like a 5 lb. cylinder is around 18.5" tall and a 10 lb. cylinder is 22" with valve from these guys. I'd rather get a larger cylinder than a smaller one. What expierience have you guys had with rig height?


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## proaudio55 (Oct 20, 2011)

@ Leaky, I had to build a DIY stand because my 20 pounder wouldn't fit inside. The total height is 32" which leaves enough space inside for the tank (which has a built in carry handle) and regulator.


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