Solid-State Discriminating Interstitial Sensor

The Discriminating Interstitial Sensor for double-wall fiberglass tanks uses solid-state liquid level sensing technology to detects the presence of, and differentiates between, hydrocarbons and other liquids in the interstitial space of the tank. Prevent serious product loss, safety and environmental issues by quickly detecting leaks in fiberglass tanks.

Key Features

  • Audible alarm (Fuel Alarm, Sensor Out) and displayed message 

  • Recorded as part of the Alarm History Report

  • Durable and accurate with no moving parts to wear out or stick

  • Withstands harsh, even icy conditions

Key Benefits

  • Detects and pinpoints leaks quickly, accurately

  • Audible and displayed alarm is triggered when liquid reaches < 0.1” high 

  • Fits 4 - 10 foot inner diameter fiberglass tanks

Product Form

Part Number



Solid-State Discriminating Interstitial Sensor for Fiberglass Tanks



Fuel Compatibility

Gas, Diesel, Kerosene, Jet Fuel, Aviation Gas, E15, Bio-Diesel 20, Bio-Diesel 100, Green Diesel, DEF, Waste Oil, Motor Oil

Alarm Notification

Normal: Sensor in Normal State – No liquid detected

Liquid Alarm: Water detected

Fuel Alarm: Fuel or Fuel / Water detected

Sensor Out: Sensor not communicating to ATG Console

Operating Principle

Optical sensor and conductivity

Product Activation Height

Fuel or Water - <0.1” (0.25cm)

Operating Temp

-40 to +122°F (-40 to +50°C)


4.3” (11cm) length, 1.5” (3.8cm) width, 0.5” (1.3cm) thick

Standard Cable

25ft (7.6m)

Tank Size

Fits 4 to 10ft (1.2 to 3m) Inner Diameter Fiberglass Tanks