CO2 questions

I'm about to get a co2 chamber built and I had some questions. First, from what I've seen people use the co2 tanks from paintball supply stores. How long does a tank like this last? (How many rats/mice can you euthanize on one tank?). Second, what is the best container to use for this? (Cooler, glass tank, etc?) what are your experiences using this method?

It does not last very long if you are serious and have a large numbers or use it on a regular basis go to a welding type company such as Airgas (http://www.airgas.com/) and get a regulator that will be your biggest expense but it is best to do it right, and get a tank, you will be able to go and exchange the tank as needed for about $15/$20 after that, this means every time you get a tank that is safe tank (CO2 tanks need to be re certified on a regular basis)

Filling of a small paintball canister is $5 and sometime done by incompetent people I had one exploding because it was overfilled.

The best kill tank are plastic tubs not too big but big enough to euthanise what you need, too big of a tank with very small number of preys will make you waste a lot of C02.

I'm planning on making a small side business out of breeding the rats so I may be euthanizing quite a few rats. I'll look into that site after work. Thanks. ^_^