# Have a question on size for CO2 Tank



## FSM (Jan 13, 2009)

it doesn't matter what size CO2 tank you get, but larger tanks last longer. Generally, it doesn't cost much more to fill a 20 lb CO2 tank than a 5 lb tank, so get as large a tank as you can fit.

A 5 lb tank would still last several months, maybe longer.


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## SPECIAL||PLANS (May 27, 2009)

the most important thing is that it will fit somewhere stored away. i bought to big a tank and now it sits out next to my aquarium and ruins the mystery of how i get those plants to grow.


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## Seattle_Aquarist (Jun 15, 2008)

Hi smcbaranek,

FSM and SPECIAL||PLANS are correct; I would get the largest tank I can that fits (with the regulator, needle valve, bubble counter installed) in the space allocated. I have a 5# tank feeding a heavily planted 45 gallon and 30 gallon and I have to fill it about every 7 weeks. I am currently looking for a 10#.


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## pandapr (Nov 10, 2008)

SPECIAL||PLANS said:


> the most important thing is that it will fit somewhere stored away. i bought to big a tank and now it sits out next to my aquarium and ruins the mystery of how i get those plants to grow.


LOL !!
And people always ask if I dive when they see the 20# CO2 tank next to the aquarium!!
This 20# lasted around a year! 
If you can fit it under the aquarium go for it.


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## cah925 (May 18, 2007)

I bought a 35lb tank earlier this year to replace a 5lb tank. It only costs me $25 to fill the 35lb tank vs $18 for the 5lb tank. The 5lb tank was being refilled several times per year. I think the 35lb tank will last at least 2-3 years. I'm at 10 months and my pressure is still at 800 psi. This was by far one of the best investments I made for my aquariums. I'm fortunate enough to have a closet right behind my 75 gal tank. I just cut a hole in the wall and ran the tubing and electrical through the hole.


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