RE: Gas leak after filling tank
That is a typical problem with the overflow/crosover network on the top of
the tank.  It usually involves the grommets and the hoses and/or crossover
piece.  Repair kits are available from several on line vendors.  If you
really know what you are doing some of the lines can be replaced without
dropping the tank but most likely you will have to drop the tank to do the
job.