# How long does 2kg CO2 last @ 1bpm?



## Jeynesey (Aug 31, 2013)

Hi all. Just a quick question regarding how long your CO2 lasts. Any examples more than welcome, e.g. a 2kg fire extinguisher running at 1 bubble per min (edit, I meant per second) as an example.

Any example of how often you have to change your tank with x amount of useage would be much appreciated - I don't need anything massively specific, just a rough idea.

Thanks.


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## Darkblade48 (Jan 4, 2008)

There are too many variables here; how long is your CO2 on for? Bubble size (i.e. how are you counting the bubbles)?

Of course, more importantly, is your entire setup completely leak free?


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## xmas_one (Feb 5, 2010)

http://www.plantedtank.net/forums/search.php?searchid=16804513


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## Jeynesey (Aug 31, 2013)

That search link doesn't work. Sorry if I have missed some often discussed topic but I can't find anything with anything I'm searching for.

I'm not after anything massively accurate, just a rough estimate for 8 hours a day, using a proper bubble counter. I have done DIY in the past and didn't like it - I just want to do it properly and I'm deciding between the different sizes of fire estinguisher / cannister.


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## xmas_one (Feb 5, 2010)

Get the biggest tank you can fit/afford.

Search for the words in the title: how, long, and co2. There's like fifty threads on it.


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## Couesfanatic (Sep 28, 2009)

Why would you want 1 bubble per minute? That won't affect anything.


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## urbach (Apr 16, 2009)

Maybe he referring to 1 bubble per second. Lowest you can go is about 0.5 bubble per seconds.


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## Darkblade48 (Jan 4, 2008)

urbach said:


> Maybe he referring to 1 bubble per second. Lowest you can go is about 0.5 bubble per seconds.


0.5 bubbles per second = 1 bubble every 2 seconds.

It is possible to achieve lower rates with a good metering valve.


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## Jeynesey (Aug 31, 2013)

Yes I meant per second, I must have had beats per minute stuck in my head from music. 

Anyway, I searched "How long CO2" and after 10 mins of reading, none of the threads answer the question. 

I dunno why it's so hard to just say "I run a 2kg at 2bps for 8 hours and I refill it every 6 months", rather than taking the trouble to post twice about how I should be searching for something that's clearly not as easy to find as you think it is. I've searched google and on here and can't find an answer.

Thank you.

edit p.s. - Darkblade, though I can't see the answer to this particular question in it, I found this thread of yours which is very good, so will save that to read later - thanks for writing it. http://www.plantedtank.net/forums/showthread.php?t=107312


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## Positron (Jul 22, 2013)

I have a 5lb canister. 2 kg is equal to 4.8 lbs. I run two tanks with co2 on 11 hours a day. The canister lasts about 3 months.


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## Jeynesey (Aug 31, 2013)

Positron said:


> I have a 5lb canister. 2 kg is equal to 4.8 lbs. I run two tanks with co2 on 11 hours a day. The canister lasts about 3 months.


Excellent, thanks very much. How many bubbles per second total?


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## xmas_one (Feb 5, 2010)

Jeynesey said:


> Yes I meant per second, I must have had beats per minute stuck in my head from music.
> 
> Anyway, I searched "How long CO2" and after 10 mins of reading, none of the threads answer the question.
> 
> ...


You're missing the point. It is going to be wildly different for everyone. Your bubbles, my bubbles and the bubbles of Fred down the street are all going to be different. There is no "ballpark" answer to your question.


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## Jeynesey (Aug 31, 2013)

xmas_one said:


> You're missing the point. It is going to be wildly different for everyone. Your bubbles, my bubbles and the bubbles of Fred down the street are all going to be different. There is no "ballpark" answer to your question.


If there is no answer to the question, why tell me to go and search for an answer to the question? 

If 10 people gave their stats / timescales, that's as good an estimation as it's possible to get and is vastly more accurate than me just guessing. As far as I know at this stage, a 1kg bottle at 1bps could last anywhere between a month and a year; I have literally no idea.


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## shambhalove. (Jan 22, 2013)

Jeynesey said:


> As far as I know at this stage, a 1kg bottle at 1bps could last anywhere between a month and a year; I have literally no idea.


Unfortunately, thats your answer. I know thats a little frustrating but theres no reason to not buy the biggest size tank you can fit and afford.

BPS is more for making individual adjustments on your specific set up, a visual aid lets call it. Its there so you can visually check the increases/decreases youve made, thats it.

Heres an example, lets say you refill your co2 tank and have to readjust your needle valve/pressure. Previously you were running your tank at 10psi and 2bps so you know you can set the pressure back to 10psi and adjust the needle valve back to 2bps and youll be back injecting at the same rate you were before.


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## Xiaozhuang (Feb 15, 2012)

I'll give a ballpark estimate of lasting 10 months, assuming your bubbles are average sized ones coming out of common bubble counters, running about 8 hrs a day.


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## Positron (Jul 22, 2013)

Total bubs per sec between the two tanks is about 8 or 9. For a sub 75 gal tank a 4.4 lb canister should last 5 months. A full 5 lb should last 6 months at least.


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## shambhalove. (Jan 22, 2013)

You can sure count faster than me lol.


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## junglefowl (Oct 30, 2012)

If there's no leak issues. It will last 10-12 months...IME!!!


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## gSTiTcH (Feb 21, 2013)

I get about 6 months on a 5 lb cyl. No idea what the BPS is, since I haven't filled the BC up in months. I run a pH controller with the target pH set to exactly 1 full point below what the water would be with no CO2.

This is actually the first time on here that I've seen this "search for yourself, it already exists" topic come up. :-/

In defense of xmas_one, all of these "How long can I expect my CO2 to last" questions appear the same, and there's no common answer. Bubble size is the varying factor, which can be influenced by the BC fluid and working pressure. I suspect barometric pressure, temperature, and a whole host of other things also come into play.


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## Jeynesey (Aug 31, 2013)

Thanks guys! I would prefer to get a 1kg because it will fit much easier in the cupboard. It sounds like that won't need refilling too often so I think I'll go for that. If people were saying that would only last a couple of months I would have gone bigger but I don't think a 2kg fire extinguisher will even fit in the stand cupboard without me moving the shelving around etc.


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