Portable Air tank for CO2 dosing

1792 Views 13 Replies 10 Participants Last post by kman, Mar 7, 2014

Roach360

Discussion Starter · Mar 6, 2014

Would it be a viable option to use a 100psi 5 gallon portable air tank to dose CO2 into my system?

I currently have a 20# CO2 tank used for carbonated beverages, and was hoping to use it in conjunction with Hyundai HPT505 5-Gallon Inflation Tank - Amazon.com as a cheap option for CO2 dosing.

I would fill the portable air tank with CO2 to ~90psi, and then control the flow coming out of that into my in line diffuser.

My tank is a 20 gallon tall with a 20 gallon sump.

Ideas on if this would work, and with what frequency I would need to refill the portable air tank?
http://www.amazon.com/gp/product/B0046402MW

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OVT

· #2 · Mar 6, 2014

I do not see a reason why it should not work. As long as you can control the delivery rate, nobody cares where the co2 is comming from.

Connecting the hose safely to a needle valve does not look to be that hard.

v3

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Roach360

Discussion Starter · #3 · Mar 6, 2014

Yep, I'll be using 1/4 poly line and a flow control, not that braided hose.

Any Ideas on how long it'll last?

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rdmustang1

· #4 · Mar 6, 2014

Roach360 said:
Yep, I'll be using 1/4 poly line and a flow control, not that braided hose.

Any Ideas on how long it'll last?

You'll have to be careful. CO2 tanks are around 850 psi and that container only holds up to 100 psi. I'm guessing you could pump some CO2 into it but probably not a whole lot due to the pressure restrictions. Technically CO2 will liquify under 100psi but I have no clue if you'll be able to pump and liquid CO2 into the 2nd tank. My guess is you won't which would mean the 2nd tank would only have gaseous CO2 which runs out MUCH faster. You'll need to be VERY careful not to pump too much or the tank will break and it could be very dangerous. You'll probably have to refill it quite often. You'll also need a high quality regulator to prevent EOTD due to low pressure. At 100 psi my tanks only last a couple days before it runs out.

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goneRogue

· #5 · Mar 7, 2014

Why even bother when you can buy a 2.5 lb tank for $50 or a 5 lb tank for $55?

http://www.aquariumplants.com/CO2_Cylinders_guaranteed_unbeatable_prices_p/t.htm

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Roach360

Discussion Starter · #6 · Mar 7, 2014

goneRogue said:
Why even bother when you can buy a 2.5 lb tank for $50 or a 5 lb tank for $55?

http://www.aquariumplants.com/CO2_Cylinders_guaranteed_unbeatable_prices_p/t.htm

Local 20# exchanges are $5.99, with the $28 air tank I don't need a regulator as I already have a flow regulator.

So, the air tank is $28 + $1 for 1/4 poly line (I already have all fittings.)

5lb cylinder is $56 plus a fill ($12 at local brew shops) and shipping + $40 for a regulator (minimum).

That's nearly 5x as much, which is why I was considering the air tank.

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jeffkrol

· #7 · Mar 7, 2014

Roach360 said:
Local 20# exchanges are $5.99, with the $28 air tank I don't need a regulator as I already have a flow regulator.

So, the air tank is $28 + $1 for 1/4 poly line (I already have all fittings.)

5lb cylinder is $56 plus a fill ($12 at local brew shops) and shipping + $40 for a regulator (minimum).

That's nearly 5x as much, which is why I was considering the air tank.

Head tells me it is doable (stupid head).. Instinct tells me it is problematic..
But first you say you have a regulator or do you assume one is on this tank which it isn't.. There is a simple control valve though..

Sorry for the silly question. Would I be able to use this for airbrushing? I want to hook this up to my compressor and have it at about 15-20 psi.
This tank doesn't have a regulator. To use it with an airbrush, you'd have to install one on the tank valve or have an airbrush with a regulator built into it.

What ever you charge the tank to is what you will get out.. only slower or faster..Of course if you set your CO2 out reg @30-40psi.. should be no problem..

I do enjoy thing outside the box.. but this would be a bit far out for me..

There is a possible issue of thermal shock to the welds weakening them...

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xxxSHyXAxxx

· #8 · Mar 7, 2014

It may be 5 x the cost bit it'll probable be 50 x less hassle. If you're going to do CO2 you might as well do it right. A miss calculation on the fill of the air tank and you'll have a pipe bomb. Plus you will not be putting in as much CO2 as you think unless you are able to get a vacuum inside the air tank. You'll just be pushing in CO2 on top of the air already in the air tank so it won't be concentrated CO2 unless you do a bunch of purge and fill cycles. This would work because CO2 is heavier than air but how much and how often do you purge so that you get the most CO2 in the air tank? How much CO2 will be wasted?

Have you thought about T'ing off the 20# and adding a needle valve so that you can run the tank and fountain off of the same cylinder?

Sent from my SGH-T989 using Tapatalk 2

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OVT

· #9 · Mar 7, 2014

+2 ^^

+$50 for a peace of mind and 2 undamaged eyes.

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Roach360

Discussion Starter · #10 · Mar 7, 2014

xxxSHyXAxxx said:
It may be 5 x the cost bit it'll probable be 50 x less hassle. If you're going to do CO2 you might as well do it right. A miss calculation on the fill of the air tank and you'll have a pipe bomb. Plus you will not be putting in as much CO2 as you think unless you are able to get a vacuum inside the air tank. You'll just be pushing in CO2 on top of the air already in the air tank so it won't be concentrated CO2 unless you do a bunch of purge and fill cycles. This would work because CO2 is heavier than air but how much and how often do you purge so that you get the most CO2 in the air tank? How much CO2 will be wasted?

Have you thought about T'ing off the 20# and adding a needle valve so that you can run the tank and fountain off of the same cylinder?

Sent from my SGH-T989 using Tapatalk 2

Overfilling it isn't an issue as I can just set the regulator on the 20# to 80 psi.

Pushing the air out is possible by just purging the tank with the pressure release on the top, as CO2 is heavier, and thanks to the Joule–Thomson effect, the temp will also allow the co2 to push the air up and out of the air tank.

Teeing is nice, but I'll have to run almost 50 foot of poly line to get from the kitchen to the fish room. And it'll look kinda terrible.

5x the cost is far more expensive than 50x the hassle for me.

So, no one has ever tried a system like this?

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Bettatail

· #11 · Mar 7, 2014

what are you thinking?

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Darkblade48

· #12 · Mar 7, 2014

As mentioned, the gauge that is on the air tank is not a regulator, and is just a manometer that measures pressure within the tank.

You would still need some way to control the delivery pressure of the gas coming out, or else you'd get the full 100 PSI, which would then quickly drop away to emptiness.

Also, there is the hassle of purging the tank each time you want to refill, whether or not the tank is even suited for CO2 use, etc.

I would not risk it.

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65535

· #13 · Mar 7, 2014

A $25 20 Oz CO2 tank with on/off or pin valve for paintball will hold much more CO2 than a low pressure air receiver.

The small receiver has to be kept around 125psi, which means any CO2 will be gaseous and at a low pressure.

A 20 Oz CO2 tank will be around 850psi, and will hold liquid CO2 which allows for much more capacity in a substantially smaller tank.

Anyways, get a 20 Oz CO2 tank and a regulator for it, you'll spend about $100-150 and get a proper CO2 system. Also you won't find anyone willing to fill that low pressure air receiver with CO2 since it's intended to be stored in vessels that test to 3000 psi.

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kman

· #14 · Mar 7, 2014

^^ this. $20 for a 20oz tank on Amazon, plus a low end reg, and you're worlds beyond what you'd get with the other system, and far less hassle.

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