Black Tank Monitor Not Accurate

[Calpop45]

Ok, sorry to bring this up yet again, but the forum search engine is, at best, frustrating, and at worst, non-op, at least for me.
2018 DSDP: OEM black tank monitor operation has degraded over the last two months, going from zero to 80% in minutes, periodically going from zero to red, usually when I dump the tank. Now it’s stuck on 100% all the time. I have been using every cleaning method I can find with no improvement. I’ve tried the rinse; rinse after adding Dawn to a full tank; rinse after using a variety of tank treatments; rinse after using the Dawn/Calgon treatment. I typically use a tank treatment powder that I’ve used successfully for years. When I clean and rinse, the water runs clear out of the tank so I suspect a problem with the monitoring system, however the freshwater and greywater guages appear to be ok.
I’ve read in this forum about fixes, but cannot locate any info. Are the sensors located in the pegboard bay? Is there an update to the system? Or a fix? I’m down to pulling the F8 fuse to bypass the monitor.
Would someone please direct me?

[Winepress]

Sensor has come loose from the tank. Access from the wetbay. Have to pull the wetbay fascia. While it’s apart, install sealevel system.

[Calpop45]

Much appreciated, Winepress, I’ll look into Seelevel. When I reinserted fuse 8 this morning, the gauge read properly. The sensor must have slipped back into place. If history is any indication, the monitor will read correctly until I dump.