View Full Version : Question about 20 lb. CO2 tank
scottracy
05-28-2004, 11:57 AM
I found a welding shop that will sale me a 20 lb. CO2 tank for $50 full with ability to swap out for refills. The only negative is its a 70 mile drive. How long will 20 lbs. last?
Scott
Richer
05-28-2004, 12:09 PM
A very long time?
Hard to say... like a lot of things in this hobby it "depends." However, I think its very safe to say that it will last the average user for quite a long time.
My 70 gallon tank maintains a CO2 concentration of about 25ppm... the 5lbs tank lasts about 6 months. So a 20lbs tank would last me for two years. Is it worth the drive? I'd say so =)
HTH
-Richer
Matt W
05-28-2004, 7:55 PM
Agreed....a long time a 5lb bottle lasts 4 months on my 125g. That 5lb bottle also cost me $75 here in town. $50 for a 20lb? Go for it...
scottracy
05-28-2004, 8:35 PM
Purchased the tank today. Drove 70 miles of beautiful Texas country highway to a little welding shop in Navasota. With tax the tank was $54. I was surprised to see that the tank was in great shape, aluminum and with rescent test dates. I must have called 30 shops before I found this place. Most of the shops wanted well over $100 for a 20 lb. I was actually looking for a 5 or 10 lb tank but this was the overall cheapest one. The second cheapest was $60 for a 10 lb tank. Just waiting on the remainder of the equipment to arrive.
Scott
Now that you've bought it, you can probably get it filled locally.
I will be astonished if you get more than 6 mons. out of a tank of CO2(even a 20 pounder).
Let us know how long it lasts for you.
Len
scottracy
05-29-2004, 8:29 AM
Six months would be fine. I was just glad to find one for the price. I was not having much luck keeping the price below $70 regardless of the size. Local guy wanted an arm/leg for a 5 lb. tank. We will see if bigger is truely better!!
Scott
beviking
05-31-2004, 10:15 AM
Originally posted by djlen
...I will be astonished if you get more than 6 mons. out of a tank of CO2(even a 20 pounder)....
Len
:confused: Why do you say this Len? Most of the quotes I've seen is 6 month plus for a 5lb-er. Wouldn't the 20 last longer?:confused:
djlen
05-31-2004, 11:26 AM
Because I have rarely gotten more than 6mons. out of a 20lb. tank. I do keep my CO2 ppm a bit higher than many, but even at 25 - 30ppm, I can't imagine someone getting much more than that. Not saying that it can't be done. Just that it has never been the case for me.
I use a 5lber to inject to a 10 and a 5gal. A 20lber to inject to a 40gal. and another 20lber to inject to a pair of 55gals.
I do get longer life out of my 20's than my 5, but nothing over 6 months.
Keep in mind that there are many variables due to kH, tank size etc., which govern the bubble rate.....hence the shelf life of a tank of gas.
One other variable: I never let my pressure go below 550 - 600psi before re-filling. I'd rather waste 1/2lb. to 1 lb. than rish a tank dump.
Len
Richer
05-31-2004, 1:32 PM
A decent needle valve should be more than enough to prevent a CO2 dump into a tank. I've been running my CO2 tank till its dry (no readable pressure in the tank) for the last 2 years, and I've never experienced a CO2 dump.
My KH is quite high (my tank has a KH of around 8-9), I run a bubble rate of about 1-2 bubbles a second and have a CO2 level of around 25-30ppm.... and my 5 lbs tank lasts for 6 months. Nearly everyone I've talked to who uses CO2 injection gets months and months of use out of even tiny CO2 tanks. Its unlikely... but perhaps you have a leak?
-Richer
125gJoe
05-31-2004, 2:42 PM
Our 10 pounder lasts almost a year.
It's switched off at night.
beviking
06-01-2004, 1:50 PM
O.k., don't get all surprised if this thread comes back up in a year or so. My buddy is trying to get me a 20lber and after my 5lber runs out (hopefully in no less than 5 months) I'll use the 20 (IF I have it by then).
Yet another experiment for the good of AC!:D