Try this instead:
drill a 1/2" hole in a plastic tank, insert the grommet, and push in the steel fitting. The fitting expands the grommet and forms a leak-proof seal. Put the hole in the bottom if you need a gravity feed, or install it in the top if you have a pump. Connect a shorter, pickup hose to the smaller barb with a weighted filter in that case.
Standard stuff for lawnmower tanks.
