Given the following information, what is the most probable cause of the problem at the lift station: 1) All 3 pumps has the same run amperage, 2) Wet well inlet is normal, 3) Well drops normally when pump #1 is running, 4) Well level rises slowly when pump #2 or #3 is running, 5) One of the pumps motors turn backwards when off, 6) Level system is reading correctly, 7) All electrical controls are on automatic.,