What CO2 cylinder size should I get?

[Aqua07]

Ok, I just ordered a regulator, diffuser, etc....now to get a paintball CO2 tank.

I'm going to mainly be using the set up on a 8 Gallon Nano.

What size CO2 canister should I get? Assuming 1 bubble every 3 seconds..how long would a 20 Oz canister last?

I have the option of going to 4oz, 12 or 20oz.

thanks

[oldpunk78]

I would cough up the few extra bucks on the 24oz. It should last a couple months at a time on an eight gallon.

[Aqua07]

For size constraints, I think I'll pickup at 20 oz tank, which will equate to about 1.3lbs of CO2 capacity.

Trying to figure out how much it should last before a refill base on feedback from others, but I"m hearing ranges from 2 month, to 6 and to even a year!!!