This internal tank sensor is usually installed in metal tanks, or on a plastic or fiberglass tank where limited access to the outside of the tank precludes installing the external sensors. It consists of sensor foil inside a PVC pipe that is easily cut to fit the tank. 

SCAD manufactures two different types of sensors that detect fresh, gray and black water levels (not for fuel).

• External Sensor: The external sensor adheres to the outside of the tank and cannot be fouled.  It can sense through plastic and fiberglass tanks up to 1/2 inches thick up to 30 inches tall (can be positioned on taller tanks toward the direction of the alarm area). This sensor cannot be used on metal tanks.
• Internal Sensor:  The internal sensor uses the same technology as our external sensor, but can be used on metal tanks.  The sensor has a 1-inch NPT threat mount.  SCAD also manufactures an SAE 5-hole to 1-inch NPT adapter, which is a common port on metal tanks.
  
  

For more information, manuals, and technical details, see SCAD's support page