The U-S Senate today endorsed a one-dollar increase in the federal minimum wage. If it becomes law, the minimum wage would reach six-dollars and fifteen cents in three years — but managers at several fast food chains say Iowa’s tight labor market has already forced them to pay that rate — or more.Diane Schaufen-Buel is the Human Resources Manager for Burger King. Other fast food chains are offering around seven dollars an hour. She says they may have to hike pay even more if they can’t find people to make and sell their burgers and fries.Schaufen-Buel says the customer may ultimately pay the price as the cost of meals are raised to pay the added labor expense.Schaufen-Buel says Burger King offers other incentives and promotions to keep employees on board.