CO2 Tank for "diving"

[Delphinus_nz]

Saw this auction on Trademe (NZ equivalent of ebay) titled "Diving Tank for CO2 I think".

Looks like someone is making up an excuse to sell something they found somewhere. Allegedly from their "no longer diving friend".
Diving Tank for CO2 I think

 

[Bob DBF]

I'm a diver and have a CO2 tank, I use it to pressurize beer kegs until I can properly empty them.


Bob

 

[Wookie]

I'm a diver and have a CO2 tank, I use it to pressurize beer kegs until I can properly empty them.


Bob

They are good for carbonating water as well.

 

[Bob DBF]

Water?
Do you know what fish do in that?


Bob

 

[2airishuman]

Typically, CO2 cylinders have a low maximum pressure (1800 PSI in the usa) which prevents them from being of much use for diving.

 

[tridacna]

I use one in my coral reef tank.