We have seelevel sensors on our Monaco, I put them in in 2012. Most recently, maybe 2 months, the gray tank sensor says 100 all the time. (when draining it goes to 95 for a bit, then back to 100) T...
I know that a few people out there think that the GEO Method isn't worth the effort but I installed my Seelevel sensors in August of 2006 and have used the GEO method periodically ever since. Occasionally (when I've failed to used the GEO Method for some time) the sensors stop work correctly. I too get my bottles of Calgon, dish or laundry soap, dump some in each tank and the sensors start working A-OK again.