Calgon & Dawn treatment for waste tank sensors issues works!

The sensors that come in the tanks are actually electric probes that pock into the tanks. They get coated and then will not conduct the low voltage power that shows the level in the tanks in fractions. RV tank Sensors are electronic
strips that are stuck to the tank and give read-outs in % to a circuit board on the wall.
Just do a Google search. A little expensive but to me well worth it.

Dusty R wrote:
The sensors that come in the tanks are actually electric probes that pock into the tanks. They get coated and then will not conduct the low voltage power that shows the level in the tanks in fractions. RV tank Sensors are electronic
strips that are stuck to the tank and give read-outs in % to a circuit board on the wall.
Just do a Google search. A little expensive but to me well worth it.

actually the factory sensors work the opposite of what you outlined. when they are not in contact with a liquid which provided a electrical path to ground they are off. Problem is if crud gets on the surface and on the sides of the tank there is a electrical path to ground even though they are not submerged. Hence the light up.

I agree the most foolproof solution is something like the sealevel system which I have, more accurate, zip troubles.

dishwasher detergent, vinegar, calgon seem to help keep the factory sensors working, dishwasher detergent has good grease cutting capabilities, better than clothes washer detergent. Vinegar is a mild acid which will help desolve crud on the sensor or tank walls, calgon softens the water and then keeps calcium etc. from building up on the tank walls.

But then the sealevel system doesn't care about any of that and it is easy to install. But not inexpensive,

I recently had to replace the grey tank in my 30-year-old MH. The black and fresh tanks have the original sensor system which is foil tape at various intervals on the tank; it's still working fine. The new tank has the dreaded through-wall system, so I added the sensor reader to work with it.

Almost invariably after dumping it still reads at least 1/3; after several days it dries out and indicates empty. Ridiculous.

If it gets to be a real problem I'll try the Mopeka "sonar" sensor.