The Holding Tank (freshwater and waste water) Monitors are a “Push to Read” system with 6 blue LEDs illuminating when fluid is present.   


The in-tank sender unit has stainless steel sensing rods that are custom cut according to the size, shape and dimensions of your tank.  


The systems are specifically designed for their specific use in freshwater or waste water conditions and should not be interchanged.


Click on the Waste Water Monitor or Freshwater Monitor page for more information.  The Product Video and Virtual Boat Show videos also provide a detailed overview on how the systems function.


Add a Vigilance Monitor to your Boat or RV tank

Our Optical Fuel Gauge can be used for gasoline or diesel tanks.  Each custom-built Sender Unit is a square PVC tube with a patented, optical sensing system built into it.  Sensors are placed along the tube at 10% or 20% intervals - depending on model.


When fuel is present, each optical sensor turns on its corresponding LED on the display.  These Fuel Gauges are “always on,” so they can be connected to your boat’s engine power or they can be independently powered and switched on and off so you can check the fuel level without the engine key.


A hinged sender can be provided for insertion into tank ports that have limited clearance.  The hinges lock in the vertical position with magnets.  See Options

Electrosense manufactures the most advanced, yet affordable Holding Tank (Freshwater and Waste water) Monitors, and Fuel Gauge Monitoring Systems.  The Vigilance line of Holding Tank Monitors  (Freshwater and Waste Water) is designed for marine and RV use.

Our systems use no moving parts and very little power. Each sender unit is custom-made, not off-the-shelf. This means that we can provide accurate monitoring for irregularly shaped tanks like those built into the fiberglass hulls of boats. Systems are maintenance-free, easy to install, and durable.

Most systems on the market use float switches, which eventually break; or they use "stick-on" sensors on the outside of the tank, which can easily be fooled into false readings by buildup on the inside of the tank's walls. Our sensors are all-electronic - no moving parts to break or get stuck. The displays can be powered by boat power or by a 9-volt battery, which means that you don't have to run any power cables. The only cable to run is the control cable between the sender unit and the display unit - we use Cat5 Ethernet cable for that, so all you have to do is plug it in - no crimping or splicing.

Holding Tank Monitor Systems

Optical Fuel Gauge Systems