Solid-State Alternative Ethanol Fluid Interstitial Sensor

The interstitial sensor for double-wall fiberglass tanks with high alcohol product uses solid-state liquid level sensing technology to detect liquid in the interstitial space of the tank. It is approved for use with high alcohol alternative fluids such as E85.

Prevent serious product loss, safety and environmental issues by quickly detecting any leaks in the interstitial spaces of 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

  • Alarm is triggered when fuel or water reaches 0.2” or when E85 reaches 0.4” 

  • Fits 4 - 10 foot inner diameter fiberglass tanks

Product Form

Form Number



Solid-State Alternative Ethanol Fluid Interstitial Sensor for Double-Wall Fiberglass Tanks


2” (50mm) Interstitial sensor riser cap kit (sold separately)



Fuel Compatibility

Gas, Diesel, Kerosene, Jet Fuel, Aviation Gas, E15, E85, E100, Bio-Diesel 20, Bio-Diesel 100, Green Diesel, DEF, Waste Oil, Motor Oil

Alarm Notification

Normal: Sensor in Normal State – No liquid detected

Fuel Alarm: Liquid detected

Sensor Out: Sensor not communicating to ATG Console

Operating Principle

Optical - looking at phase changes in the light beams by causing them to interact or interfere with one another

Product Activation Height

Fuel or Water <0.2” (0.5cm); E85 <0.4” (1cm)

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) I.D. Fiberglass Tanks