I have the Garnett SeeLevel tank sensors in my Trilogy. Previously I owned a 2008 Cedar Creek 37RDQS that had 4 tanks.
After a couple of years the factory tank sensors were starting to fail & provide inaccurate readings. In researching solutions, I found the SeeLevel system. It mounts to the outside of the tank and uses capacitance to read "through" the tank. This means the sensors would never be fouled since they are not in contact with the contents.
The system and display panel only use four wires (+12, ground, network signal, LP) to read all of the tanks. Each tank sensor is coded for the type of tank it is mounted to. The display panel allows you to select the desired tank. A signal is sent to the tanks and the tank you are asking for information from, responds.
With the same system installed on my Trilogy, I wanted to add an additional feature; a second display. This is possible due to the well designed system. I added the additional display panel in the basement at my docking station.
(Sorry, not sure why the image is sideways)
Now when I am outside emptying the tanks, I can monitor the level full time and know how full or empty it is as the display reads in percentage of full capacity. I can also monitor the fresh water as it is filling to know how close it is before it over flows.
Check out their products on their website. Trust me, if you try one of their systems you will wonder why you didn't do it sooner!
SeeLeveL Liquid Level Gauges by Garnet Instruments Ltd.
This is the one I installed that includes LP tank readout large onboard tank only)
SeeLeveL Gauges by Garnet Instruments Ltd. - Model 709-4LP
2014 Dynamax Trilogy 3850RL - South Hampton Interior, Full Body Paint (Black / Silver / White), MOR/ryde Independent Suspension, MOR/ryde Disc Brakes, ONAN 5500 Generator, Progressive Industries HW50C w/Dual Display, Winegard HD Dish w/DirecTV, Washer & Dryer, iSprings 7-stage Reverse Osmosis Water Filter, Trail-Air Flex Air Pin Box, Third AC installed, AC Voltage/Amp Meters, DC Amp Meter.
Retired USAF - Full Timers!