A gasoline vapor treating system includes a single hydrocarbon filter apparatus interconnected to a fuel tank having a range of vapor pressures therein, said filter apparatus receiving hydrocarbon vapors from said tank for one vapor pressure in said fuel tank and said filter apparatus delivering air and hydrocarbon vapor to said tank from said filter responsive to another vapor pressure in said tank lower than said one vapor pressure, said filter operated serially between hydrocarbon loading and hydrocarbon unloading cycles without reference to any other hydrocarbon removal apparatus. A balance nozzle includes a mechanism to mechanically operate a vapor valve therein before the fuel valve is opened.