Where can I get a co2 tank filled in Rockford, anyone?
There is a Brew & Grow in Rockford, that's what I go (by me) to exchange my CO2 tank. They only exchange, so no refills. If you are somewhat tied to your CO2 tank, find a welding shop that refills them, otherwise Brew & Grow is where to go. I believe they only do exchanges on 5lb and 20lb tanks so if you have a different size, find a different place to go.
Brew & Grow
3224 S Alpine Rd
Rockford, IL 61109
If you are just doing CO2 for a nano tank, you could probably get away with using a paintball tank and you can refill those at any sporting goods store.