this is wierd! black tank senor problem

These "monitors" are notorious for giving false readings. Sludge, paper, simply being what they are....
When stationary, I make a habit out of dumping the black tank every 3 days or so. The Gray water valve is always open.

When traveling, every morning. Don't want that stuff sloshing around...with the odors it sometimes gives us....FROM sloshing around.

Experimenting over the years, I found, with the black tank, after 4 days, it "burps" when flushing. THAT is the big clue to dump.

If it is possible to get to the area where the sensors are you may be able to add an in tank sprayer. Just put a quick disconnect on a short piece of hose so you can switch between tank cleaners.

For some reason they installed my sprayer in the opposite end which does fine for cleaning the bottom of the tank but the spray does not clean the sensor area.

Even with that ours can act up like yours so I actually installed a deck access plate and can use my pressure washer.

I also found that a cup of liquid Dawn left sitting in the tank as long as possible seems to keep it clean,

We are full time and do not use any chemicals. Just plenty of water.

Mr. Tohare,

The Tecma toilet in our '08 Dynasty drove me nuts sometimes. Ours did just as you describe, the black tank would be empty and would show green then flip back and forth to red or sometimes stay on red. Of course when it's red, you have to hold the button to get a flush.

Our Tecma toilet was also a macerator toilet. What helped tremendously was to 'back-flush' the toilet. With you having two toilets, this may not work.

I would fill the black tank with the sani-con system until the water started to come up into the toilet. Then I would run outside and release the black valve to get a good flow of water gushing out into the sewer drain. This worked to clean out the macerator part (I think) and it would work fine for a while.

Safe travels,
MM.

We have the same problem with our Techma toilet in our MH. The Techma uses ultrasonic sensors which are glued to the side of the tank. It can have one or two sensors depending on how it was installed. The LED will will go yellow then red. It's common for the LED to go red well before the tank is actually full. Exactly why I don't know but it does. I removed my Techma sensors, cleaned (by grinding it flat) the tank side and re-glued them, and it didn't help. Now I will un-plug the two Techma sensors and just go with the regular pin sensors. Not sure how the Techma's computer will react when I do this however. MH is in Winter storage right now so it'll be a while before I can try it.

Do both the black and grey tanks dump through the same outlet valve? Is there a chance that you left the grey tank (small valve) and the black tank (large valves) open... with the result that grey water is entering the black tank?? If not.. you're right... this is truly weird!!

Usually there is a slime/debris buildup on the wall of the tank. The Tecma's is a glue on sensor and picks up the inside with a sonic type electromagnetic sensing system. Buildups can cause it to go crazy and not sense the correct inside level. Try multiple flushings (4 or 5). This means filling the tank FULL and then dumping. It is best to have a clear adapter at the sewer outlet on the hose. This way you can watch if you get debris after each flushing. You may only see debris as the last 5 to 10 gallons rush out on each flush. Doug