When drying my fuel there is a dark film on top of fuel that is drying, is it possible that this is glycerin going through the spray nozzle or is there something else that could be making this residue on top of my good fuel.

I'm no expert but I wouldn't think it's glycerin. Glycerin is heavier than biodiesel and would settle to the bottom, rather than film up on the top. Perhaps it's some leftover soaps?

Perform a 3/27 test on the fuel; I am thinking it is under reacted, but could just be a soap layer.The 3/27 should tell you which by the process of eliminating one.