# How long does your CO2 last?



## mmelnick (Mar 5, 2010)

I have a 40 oz CO2 tank that I am planning on using on a 54 gal corner tank. I have the back sectioned off so it only holds about 30 gallons of water.

From reading in the thread about paintball tanks I was lead to believe that most people get a few months or even a year or more out of a 24 oz. tank on an aquarium around 20 gal.

The guys at my LFS say that they go through a 10 lb CO2 tank on a 20 gal tank every 5-6 weeks and they also shut it off at night so it's only running 1/2 the time.

So I thought I'd ask you guys so I can know what I'm getting myself into before spending all this money :smile:

To get a good idea I think we'll have to know the following...

1) What size CO2 tank are you running?
2) What size aquarium is it on?
3) How many bubbles per second?
4) Does it run just in the day or 24/7?
5) How long does your tank last?


Thanks roud:


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## comatoast (Mar 11, 2009)

CO2 Tank: 5 lbs.
Aquarium: 26 gal. bow front
BPS: unclear- using AP's electronic regulator w/o bubble counter, but d/c stays light green
Runs about 9 hrs./day (on 1 1/2 hrs. before lights, off with lights)
Lasts about 5 months.
Hope this helps.


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## EntoCraig (Jun 7, 2010)

10lb. Co2 tank. lasts about 9 months. roud:


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## mmelnick (Mar 5, 2010)

EntoCraig said:


> 10lb. Co2 tank. lasts about 9 months. roud:


How many bubbles per second? Are you running it 24/7, or do you shut it off at night?


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## Centromochlus (May 19, 2008)

Co2 tank size: 5lb.
Aquarium size: 90 US gallons
Regulator: GLA
BPS: ~6
Diffusion: Via glass diffuser w/ power head
Runs: 8 hours per day
Lasts: ~4 weeks


Sent from my iPhone using Tapatalk


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## EntoCraig (Jun 7, 2010)

AzFishKid said:


> Co2 tank size: 5lb.
> Aquarium size: 90 US gallons
> Regulator: GLA
> BPS: ~6
> ...



You need a 20lb!


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## fitness2go (Oct 13, 2005)

Something is wrong there! They are going through a 10# CO2 tank every 5-6 weeks on a 20 gallon tank and it doesn't run at night!?!? Something is definitely not right.

I have been using 10# tank and running over 8 bps/8 hours a day for over a month and the thing is still 3/4 full.

David



mmelnick said:


> The guys at my LFS say that they go through a 10 lb CO2 tank on a 20 gal tank every 5-6 weeks and they also shut it off at night so it's only running 1/2 the time.


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## mmelnick (Mar 5, 2010)

fitness2go said:


> Something is wrong there! They are going through a 10# CO2 tank every 5-6 weeks on a 20 gallon tank and it doesn't run at night!?!? Something is definitely not right.
> 
> I have been using 10# tank and running over 8 bps/8 hours a day for over a month and the thing is still 3/4 full.
> 
> David


That's what I said. I asked if he had a leak or something???


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## chad320 (Mar 7, 2010)

I run a 10#er on a 65g at 4-5 BPS thats shut off at night and it lasts about 3 months.


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## Wasserpest (Jun 12, 2003)

chad320 said:


> I run a 10#er on a 65g at 4-5 BPS thats shut off at night and it lasts about 3 months.


I run about the same bubble count with the same bottle size/weight and shutting off at night, only diff is that it lasts 9-10 months.


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## chad320 (Mar 7, 2010)

Wasserpest said:


> I run about the same bubble count with the same bottle size/weight and shutting off at night, only diff is that it lasts 9-10 months.


Maybe mine also has a leak. Whats your photoperiond that its on? Mines 10 hours.


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## Wasserpest (Jun 12, 2003)

Mine too... :smile: Noon to 10 pm.

Maybe your bubbles are bigger. Or the refill place doesn't refill your tank all the way.


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## chad320 (Mar 7, 2010)

Wasserpest said:


> Mine too... :smile: Noon to 10 pm.
> 
> Maybe your bubbles are bigger. Or the refill place doesn't refill your tank all the way.


They fill it all the way. I was also wondering if P.S.I. had an influence as well as the length of your line to the tank. Mines at 15 PSI, and about 6 ft. of line.


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## Darkblade48 (Jan 4, 2008)

An increase in pressure as well as the length of line to the aquarium would increase the amount of CO2 lost due to permeation through the tubing, but the magnitude is on the 10^-7 to 10^-9 scale, I believe.


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## mmelnick (Mar 5, 2010)

Interesting. So if I judge from the range of tank life that everyone has reported I might get anywhere from 2-3 weeks to half a year then...


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## Vancat2 (Jun 23, 2010)

i think a lot of people have leaks they aren't aware of.


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## Wasserpest (Jun 12, 2003)

chad320 said:


> They fill it all the way. I was also wondering if P.S.I. had an influence as well as the length of your line to the tank. Mines at 15 PSI, and about 6 ft. of line.


What kind of line? I heard silicone can be a bit leaky. I use thick-walled PU tubing that's specifically recommended for CO2. The PSI doesn't really come into play, since we have low pressure after the needle valves (no tubing between regulator and needle valves in my case.

Agreed though, most likely some of us have small leaks. :icon_eek:


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## wkndracer (Mar 14, 2009)

Light quality, intensity, photo period, plant mass, water movement (everything is a variable :help. I can add details on mine as I document trends tracking my tanks using Excel spreadsheets. This (I hope) combined helps answer your question.
I'm injecting two 75g tanks off the same 20lb cylinder. Substrate, drift wood, rock, yada yada in the tanks actually puts them at 60g and 63g respectively. 
Using 2 American Marine controllers on separate solenoids driving for 30-45ppm based on the CO2, KH, pH relationship and drop checkers using 4dKH solution. Rex style down flow reactors are used after the canisters for adding the CO2.
Lighting is Current brand T5HO 4x54w, 2 - 54w 10K, 2 - plant grow or life grow (67K primary) paired running 8hrs. w/4hr burst on the second pair. Fixtures are mounted on short legs over All Glass tops with the bulbs 20" above the substrate making it ridiculously high based on Hoppy's posted work on Par and intensity here in the lighting section.
I do not shut down the controllers at night. Experience has been that rarely do the solenoids go active after the lights shut down and pH , CO2 remain at consistent levels 24/7. (IMO) minimum gas loss, less timers, less to forget.
I do not run air stones at night.
I do not have any problems with my live stock.

All that being posted here's what I think I'm getting for time on a tank.
Cylinder was swapped out at <500lb. high side pressure after running the tanks for 16 months. I weighed the cylinder after pulling it then took it outside and drained the remaining pressure to atmosphere. Weighed it again finding it still had 2lbs. of gas.
(16 months) 18lbs/16m = 1.12lbs. per month

Cylinder was swapped out at 500lb. high side pressure after running the tanks for 16 months, 21 day's. I weighed the cylinder after pulling it then took it outside and drained the remaining pressure to atmosphere. Weighed it again finding it still had 3lbs. of gas.
(16 months, 21 day's) 17lbs/16.66m = 1.02lbs. per month

Still more variables/errors.:icon_sad:
Some months = 28days others 31d (?). Based my count on 30d per month. My bathroom scale only registers whole pounds. 

123g injected to 30-45ppm at high light for me is about 1lb of CO2 per month.
(HTH)

Another member asked this awhile back so I dug up my tracking info also not included before was the amount of tubing. =20 feet.


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## mmelnick (Mar 5, 2010)

wkndracer said:


> Light quality, intensity, photo period, plant mass, water movement (everything is a variable :help.


True, they are variable, but unless you have a PH controller or something fancy lijke that then they don't matter to the CO2 tank life.

How many BBS are you running and how long is your CO2 on? That should be the only thing that makes any difference.


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## wkndracer (Mar 14, 2009)

mmelnick said:


> True, they are variable, but unless you have a PH controller or something fancy lijke that then they don't matter to the CO2 tank life.
> 
> How many BBS are you running and how long is your CO2 on? That should be the only thing that makes any difference.


It all does matter if you think about it further.
If your only tracking and adjusting bps with a simple drop checker then to get what color/ppm you want you adjust +,- on indication of color. Then use a timer to set duration.
Huge plant mass more gas needed, little = less.
High light the plants use more, low light = less.
Tank turn over and surface movement (out gassing).
Type of diffusion method. (better or worse) 
I can't count bps because the flow rate is huge into the reactors, the bubbles are a steady stream.
Full to empty on the cylinder and the day on the calendar it all stops and starts is how long I think it lasts.


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## mmelnick (Mar 5, 2010)

wkndracer said:


> It all does matter if you think about it further.


 
I do agree with that, but I can only convert what you're running for bubbles per second for so long per day to my size of tank on my setup. I'm just saying that I can't really do the math on the other factors to make them equate out to a set time for my personal setup.

But thatns for the info roud:


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## wkndracer (Mar 14, 2009)

mmelnick said:


> *I'm just saying that I can't really do the math on the other factors* to make them equate out to a set time for my personal setup.
> 
> But thanks for the info roud:


LMAO but I can't either I just recorded information for over a year and added stuff up.









To get a good idea I think we'll have to know the following...

1) What size CO2 tank are you running? 20lb.
2) What size aquarium is it on? 123g volume
3) How many bubbles per second? can't count it
4) Does it run just in the day or 24/7? yes 24/7 based on demand
5) How long does your tank last? gas use is one pound per month for two 75g tanks.

Setting up with a drop checker / timer for control. Starting the gas 1/2 hour before the photo period and shutting off 1/2 before the lights do should do great for ya. How long a cylinder lasts before refilling it's still cheap to do long term.


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## calvert (Apr 29, 2010)

on for 8 hours a day. ~5bps. 5 lb'er lasts 3 months.


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## mmelnick (Mar 5, 2010)

calvert said:


> on for 8 hours a day. ~5bps. 5 lb'er lasts 3 months.


Thanks. Keep em coming... roud:

And happy 100th post to me :icon_lol:


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## chad320 (Mar 7, 2010)

Wasserpest said:


> What kind of line? I heard silicone can be a bit leaky. I use thick-walled PU tubing that's specifically recommended for CO2. The PSI doesn't really come into play, since we have low pressure after the needle valves (no tubing between regulator and needle valves in my case.
> 
> Agreed though, most likely some of us have small leaks. :icon_eek:


I use the blue stuff designed for Co2. Guess I didnt realize there was a better alternative. Where do I find the stuff you use? I cheacked for leaks about a year ago, guess I better check again. Something about soap on my reg bothers me tho


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## flowmsp (Feb 6, 2010)

5# Co2 tank
100g Tank
Unsure of bps
On for 8 hrs/day
About a month. 

Hmm i think i may see about a 10# next trip to the welding supply lol.


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## chad320 (Mar 7, 2010)

My welding supply will take your 5#er for trade + cash towards an upgrade.


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## flowmsp (Feb 6, 2010)

Yeah i like where i go, bring it in, they hand me a filled one and $16 bucks and im gone. Wonder if the 10# will be $30 or cheaper?


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## chad320 (Mar 7, 2010)

Close for steel. I think I paid $27 to upgrade mine to a 10# + the fill cost.


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## calvert (Apr 29, 2010)

chad320 said:


> I use the blue stuff designed for Co2. Guess I didnt realize there was a better alternative. Where do I find the stuff you use? I cheacked for leaks about a year ago, guess I better check again. Something about soap on my reg bothers me tho


i use clippard tubing on my setup a listed above where my 5lb tank lasts me a good 3 months.










i'm actually selling off the rest of the spool that i ordered in case you're interested. if you search for clippard tubing on ebay i believe it's the only listing there is... either way, my name here resembles my seller name there so you know which one is mine.

apologies in advance to the mods if i'm not allowed to do that. i thought direct ebay links were a no-no but mentioning things indirectly was ok--i could be wrong though.


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## talontsiawd (Oct 19, 2008)

20lb tank, 29 gallon aquarium, unknown bubble rate. I also have a short photo period so it is only on for 6 hours a day. Lasts over a year. Huge tank for my aquarium size, I got it for free though.


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## jcardona1 (Jun 27, 2008)

10lb tank
57g aquarium (with overflows & sump)
BPS: too fast to count, maybe 6-8pbs?
Lasts 2-3 months


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## happi (Dec 18, 2009)

10lb co2 tank
50g fish tank
BPS: unknown/ i try counting looks like 5-6BPS to me.
Lasts: been using it for last 6 months and its still going. 

i think room temperture also effect the co2


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## herns (May 6, 2008)

mmelnick said:


> To get a good idea I think we'll have to know the following...
> 
> 1) What size CO2 tank are you running?
> 2) What size aquarium is it on?
> ...


-20lbs
-20G
-5 to 6bps
-Controlled by PH controller set to PH6.2. ON: 1 hr before light starts. OFF:1 hr before lights is turn OFF.
-5 mos. and counting.


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## dubvstudent (Jan 10, 2009)

Wasserpest said:


> Mine too... :smile: Noon to 10 pm.
> 
> Maybe your bubbles are bigger. Or the refill place doesn't refill your tank all the way.


This is what I have always wondered about the BPS measurement. What is a standard size bubble?

I feel like each bubble counter, depending on the size of the gas inlet, is going to produce a bubble of a different size. Anyone agree?


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## hbosman (Oct 5, 2006)

1) What size CO2 tank are you running?
*20 OZ paintball cylinder*

2) What size aquarium is it on?
*46 gallon BowFront*

3) How many bubbles per second?
* N/K*

4) Does it run just in the day or 24/7?
* 8 hours per day*

5) How long does your tank last?
*4 to 5 weeks*


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## Sharkfood (May 2, 2010)

> I feel like each bubble counter, depending on the size of the gas inlet, is going to produce a bubble of a different size. Anyone agree?


The variance in inlet size won't make much difference. What liquid you fill your counter with can significantly alter bubble size however.


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