I recently replaced an old sump pump with a new submersible Flotec with a floating switch. This switch goes on at 14". My problem is that the water never seems to get that high. However there seems to be plenty of water in the system since when I manually turn the pump on, the water that leaves is quickly replaced. What can I do? How do these switches work? If I change its position (more/less slack) on the pump will that help? Where can I get a different switch? Or do I have to buy a new pump?