# CO2 Tank Size



## mattguzi (Nov 14, 2006)

I have a 75 Gal setup and am upgrading from DIY CO2. I know it's not an exact science, but is there any rule of thumb I can go by to figure out how long a 5# cylinder will last (vs. a 10# or 20#). I'm planing to use an external in-line reactor for CO2 diffusion.

I don't think a 20# will fit in my cabinet, and I haven't found a local distributer to sell/refill a 10#. A 5# cylinder is the easiest solution, but I don't want to be having to run out to refill it too often. Any kind of guideline or personal experience would be helpful. Thanks!


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## mulita (Jul 31, 2007)

I am using a 5# Cylinder in my 30gal aquarium wall and it last about 2 month sustaining 30ppm CO2 level during 11 hrs a day with 1.5 watts/gal.

I would dare to guess that the same size will hold your aquarium for about a month. Of course it may vary according to light level, light hours and target CO2 ppm's that your looking for, but it will be very close to it.

Have you asked your local supplier if they will refill your tank if you brought it? If they agree you can get a 10# cylinder as far as valve used is a CGA320


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## orlando (Feb 14, 2007)

That sounds very wrong. I use 5lb cylinders and they last 1 year.


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## mulita (Jul 31, 2007)

orlando said:


> That sounds very wrong. I use 5lb cylinders and they last 1 year.


Wow, that's a lot, now a have homework to review my system for leaks. I will love that it holds 6 months at least. How many drops per second do you have?


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## orlando (Feb 14, 2007)

I cant even count them they go by so fast.


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## mulita (Jul 31, 2007)

I have about 1.5-2 drops per second, so that make it worst and I sure have leaks in my system


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## orlando (Feb 14, 2007)

Use soapy water, or windex. More soap than water ..


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## mattguzi (Nov 14, 2006)

Orlando, what size tank do you have? 
What do you each of you use for diffusion?


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## mulita (Jul 31, 2007)

Orlando:
I just reviewed the system and there are no leaks appearently, I will review for this reload. it may be related with the HOB Filter that I am using but normally I maintain water line high.

Matt:
I am using a Red Sea CO2 Reactor 500 with a 5 lbs cilinder


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## Dany (Oct 28, 2006)

mulita said:


> Orlando:
> 
> I am using a Red Sea CO2 Reactor 500 with a 5 lbs cilinder


What type of tubing are you using?


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## orlando (Feb 14, 2007)

mattguzi said:


> Orlando, what size tank do you have?
> What do you each of you use for diffusion?


I use this..


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## mulita (Jul 31, 2007)

Dany said:


> What type of tubing are you using?


The tubing that I got with the package (From DT Aquarium) it is 3 mts black tubing. I actually place some soap on it to check it but it looks fine. one month have pass since my last reload, so I'll check on this.


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## Rex Grigg (Jan 22, 2004)

mulita

You have a leak. At 1-2 bubbles per second a 5 lb cylinder should go for a year. The 5 lb cylinder feeding my 20 gallon just ran out and it gets 2 bps and it went 14 months.

You need to use a thick soap and water solution to check for leaks. Brush it on and wait 10 minutes. Also make sure your regulator nut is TIGHT.


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## mulita (Jul 31, 2007)

Rex Grigg said:


> mulita
> 
> You have a leak. At 1-2 bubbles per second a 5 lb cylinder should go for a year. The 5 lb cylinder feeding my 20 gallon just ran out and it gets 2 bps and it went 14 months.
> 
> You need to use a thick soap and water solution to check for leaks. Brush it on and wait 10 minutes. Also make sure your regulator nut is TIGHT.


Thanks, I will.


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