co2 tank size

I would go as big as you could afford money- and space-wise...just means you have to fill it up less often.
 
for my 30 gallon tank what size co2 tank should i go for?
2.5
5
10
20

thanks!
-chris

I went for a 5lb tank on my new 30g. The 2.5lb was not readily available in my area, and the 5lb fit nicely into my storage cabinet in my stand. I'm hoping to get several months out of it. This is my first pressurized venture though, so we'll see.
 
AquariaCentral.com