Aero All-Gas on Main street in Hartford. They will refill. A 5# tank is $10. A 20# tank is $18. You can walk in and, as long as all the guys aren't on their lunch hour, walk out about 5-10 minutes later with your tank(s) filled.
3150 Main Street
Hartford, CT 06120
So I went to Hogan's Alley today, still $10. Thanks for suggesting them.
I will try shoreline in Hamden to fill a few tanks this week and post update.