Auxiliary gas tank

I have a F250 and a 5 wheel that has perfect specs for the truck but a heavy load (auxiliary tank} would hurt my weight. I plan to have two 5 gal cans of diesel to keep in the bed. Sooo, I bought a siphon today with two 52" hoses both ways. They had 2 to select from one was a bulb like a marine bulb and the one I bought has a pump that you "pump". Now I would hope that I will not have to pump the entire 5 gals into my truck and by pumping a few times would start and drain my 5 gal containers. Would either (Marine bulb or pump} do this????