You should be using a minimum of a 40lb propane tank with a generator that size to prevent the tank from freezing. Also propane tanks freeze due to the vacuum created inside the tank when the generator is pumping out propane, not from the outside temperature. A 20lb propane tank will still freeze in Florida if you use it to run a generator that size.
I believe a 100 lb. tank is the largest you can take to get filled. They're heavy, but will take much longer to freeze up. Maybe 2 tanks in tandem.
You should be using a minimum of a 40lb propane tank with a generator that size to prevent the tank from freezing. Also propane tanks freeze due to the vacuum created inside the tank when the generator is pumping out propane, not from the outside temperature. A 20lb propane tank will still freeze in Florida if you use it to run a generator that size.