After 7 years of full timing, holding tank sensors now WORK!

I bought this rig in 2005 - a year old from the original owner. As many have experienced, the holding tank sensors have never really been reliable - the black tank sensors worse than the grey tank.

If you search my posts, you will not find a shortage of my posts telling other posters to give up on the hope of the holding tank sensors working properly. Well, hopefully it is only crow I need to eat, as my tank sensors are now working perfectly! There is hope! How did that happen, you ask?

Let me start by describing my typical holding tank protocol over the years. I immediately started using the rig for full-timing. I would typically stay in one location for several weeks or months. As one would expect, I would leave the black tank closed until it needed dumping. Since the sensors were pretty unreliable, I could tell from the way the toilet flushed when it was getting full.

The grey tank I would typically leave open (especially since I use the washer/dryer alot), until I felt it was getting close to time to dump the black tank. I would then dump the black tank, use the factory-installed tank flush system to flush it, then dump the grey tank which would "clean" the stinky slinky. Mind you, the tank sensors remained unreliable. One other important point - in preparation to leave a location, I would always dump so I would be traveling without the added weight in my holding tanks. One other unfortunate note - in the last year or so, the factory-installed black tank flush system has clogged and no longer works.

Then earlier this year, I was in a situation where I was parked for 4 months and needed to use a macerator to dump. I had bought the Flo-Jet system. I followed the recommendation to dump the black tank, then shut off the macerator and open the grey tank valve to let the grey water back flush into the black tank. The macerator also has a water hose connection on it so you can back flush with fresh water, which I did a few times during my stay there.

With all this, I started to notice the sensors on my tanks behaving differently, but still not perfectly. When I left this location where I needed the macerator, I stayed for a week at a State Park where I had no sewer. While there, my holding tanks of course started to fill. Rather than dumping as I left, I decided to let the contents slosh around during my 400 mile journey to my next stop. I didn't add any ice cubes or Calgon as you might read about in other posts. Just drove.

I hope this is not too much information (TMI), but when I arrived at my destination and dumped, through the clear sewer connection I have I could see that the contents of the black tank had been thoroughly "blended". As it drained, there was not a sign of any solids - TP or otherwise. I was also surprised at the "solids" that came out of the grey tank - some black and some white. Clearly alot of buildup of soap scum, kitchen matter and such in the grey tank over the years.

Since I no longer needed the macerator but like the back-flush idea, I purchased the Flush King that would enable me to continue using the grey tank contents to back flush the black tank. After just a few dumps and back-flushes, the sensors were clearly behaving differently. Still, the black tank was not showing empty after dumping. Referring to the manual, I removed the instrument panel and used a screwdriver to calibrate the LED readout so that it read empty after I dumped.

Now when I dump and back-flush (using the grey tank only - not using fresh water to back-flush either tank), the indicator lights magically go to EMPTY. And as the tank fills, they magically indicate the increased level. Suffice it to say that I had long ago given up on factory holding tank sensors as a joke that would never work. I just happened upon a sequence of events that proved just the opposite. I'm disappointed that my factory-intalled black tank flush system is inop, but it seems that this back-flush method, possibly combined with a drive-and-slosh strategy might just be the answer.

I hope this is helpful to others. Happy Dumping!