# CO2 Costs



## kadamar (Sep 1, 2008)

Hi Folks. I have been researching the costs of various pressurized CO2 tanks and the cost to operate them. I have a 72 gal tank which I plant to heavily plant. What I wd like to know, is how long will a 5 or 10 pound cylinder last. I can rent a large tank that will hold 57 pounds of CO2 for $95 cdn a year and cost approx $65 to fill it. I am thinking that with 57 pounds of CO2 it should last at least 2 or 3 years but I need to know how long a 5 or 10 pound cylinder wd last.

Thank you

David


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## houseofcards (Feb 16, 2005)

kadamar said:


> Hi Folks. I have been researching the costs of various pressurized CO2 tanks and the cost to operate them. I have a 72 gal tank which I plant to heavily plant. What I wd like to know, is how long will a 5 or 10 pound cylinder last. I can rent a large tank that will hold 57 pounds of CO2 for $95 cdn a year and cost approx $65 to fill it. I am thinking that with 57 pounds of CO2 it should last at least 2 or 3 years but I need to know how long a 5 or 10 pound cylinder wd last.
> 
> Thank you
> 
> David


It really depends on the setup and how demanding it will be for co2, but generally speaking a 10lb cylinder we last between 10 and 12 months for a 72g.


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## kadamar (Sep 1, 2008)

...thanks for your input; that gives me a base line.
David


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## tfmcder (Feb 22, 2006)

I have a 10lb on a 90G at 1-2bps and it has been up for about 14 months so far. It is on a timer for ~8 hours/day.


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## Ultimbow (Sep 10, 2005)

have 77gal have 5gal co2 tank between 5 to 7 month to empty


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## davemill (May 3, 2004)

Have 10lb on a 72g at 1-2 bubbles per second, 24 hours per day. The cylinder lasts about 12 months.


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## hooha (Apr 21, 2005)

wow, a 10lb last me only 3-4 months on a 75 gallon. a 65 pound tank sounds crazy-large. The asthetics of having a 4 foot pressurized gas tank would be my concern.


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## CaptainNemo (Jul 11, 2008)

I have a 50# cylinder, I just keep it in the closet so nobody sees it. I got it for free, so I can't complain, and I just run all my tanks off it. The worst thing about the big cylinders is lugging them around to get refilled. A 50# weighs around 200# empty, 250# full. 

Even though they remember what I'm doing with it, the guys at the welding supply company still give me weird looks when I slide the thing into the back of my Subaru. 

I'd say unless you want to run multiple tanks or have to drive really far to get cylinders exchanged, get a smaller one. Big ones are heavy.


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## kadamar (Sep 1, 2008)

.....good points, I think Iam going to opt for a 10pounder. If I ever get multiple tank disease I may go for a bigger tank.


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## hooha (Apr 21, 2005)

fyi one of the local LFS has tried to do multiple tanks on one co2 cylinder and it was a big headache. The bought the manifolds available online to hobbyists and had issues keeping the rate consistent for all the tanks. They had to buy a different regulator that could handle the pressure for those systems (or something like that). It can be pretty difficult getting a multiple-aquarium system from one CO2 tank.


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## Headbanger (Aug 16, 2008)

I am just a dumb Rhodesian that wants to my 2 cts. worth Question are you useing mickey mouse gallons or Imperial gallons

72 m/m gallons at 3.78 lts per gallon is 272 lts.
72 Imp gallons at 4.545 lts per gallon is 327 lts 
so at an average of 1.5 grams per 100 lts per day 
so 1.5 gms x 2.7 lts is approx 4 gms per day.
so a 57 pound cylinder will weigh 57 / 2.2 = approx 26 kgs
now divide that by 4 grams 26kg = 26000 gms / 4gms = 6500 days or 17.8 years 
sock it to me baby


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## stuckintexas (Aug 12, 2008)

hooha said:


> fyi one of the local LFS has tried to do multiple tanks on one co2 cylinder and it was a big headache. The bought the manifolds available online to hobbyists and had issues keeping the rate consistent for all the tanks. They had to buy a different regulator that could handle the pressure for those systems (or something like that). It can be pretty difficult getting a multiple-aquarium system from one CO2 tank.


what if you have a valve going to each tank? could you then just use one large co2 tank and run that to a manifold and then between the manifold and each tank just have individual valves with bubble counters?


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## davemonkey (Mar 29, 2008)

I'm no mathematician, but assuming Headbanger's calc's are correct:

Even if you lost 20% of your CO2 to poor tubing and doubled the injected amount to 8 grams, then you still have enough to last 7 yrs + in that size tank.

-Dave


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## Headbanger (Aug 16, 2008)

This info of 1.5 gms per 100 lts per day came from "Dennerle " of Germany at the begining of 1980 just before I left the home country


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## CaptainNemo (Jul 11, 2008)

> fyi one of the local LFS has tried to do multiple tanks on one co2 cylinder and it was a big headache. The bought the manifolds available online to hobbyists and had issues keeping the rate consistent for all the tanks. They had to buy a different regulator that could handle the pressure for those systems (or something like that). It can be pretty difficult getting a multiple-aquarium system from one CO2 tank.


I have never had trouble with mine, and I'm not sure why you would. I have 4 tanks, one with 2 reactors, running from the same cylinder/regulator.



> what if you have a valve going to each tank? could you then just use one large co2 tank and run that to a manifold and then between the manifold and each tank just have individual valves with bubble counters?


That's pretty much what I do, just need to have an individual needle valve for each diffuser. I could see where you'd have trouble if you tried running multiple diffusers from one needle valve. My system is so diy/rigged/cheap and it works great for me, I can't see how it could be hard to do with GOOD equipment.


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