What is the right way to go about this? I have a 40gal tank I would love to put in the bed but I have no clue on what is the correct way to tie the aux tank into the stock tank. I know you tie it into the filler neck but do you just tie a line directly in? Will the Aux tank just keep the stock tank full until the aux tank is empty? Do you have to worry about over filling the stock tank? Or does there need to be a valve added inline? Like a 12v solenoid to control the aux tank.