Cleaning the Gray water sensors?

I am so careful, but I obviously have got something on the sensors in the Gray water and it was stuck on 2/3. It will register full, but will never go below 2/3. The motorhome is almost new and the tank is truly emptying. I tried putting some Tide in the tank while we traveled, and now the sensor registers 1/3 so I have made progress. Does anyone have an idea as to what I can put in the Gray to clean those sensors. I am assuming they have grease or something of that nature.

I wondered about putting some coffee grounds while we travel.

Anyone have an idea.

My black tank sensors are stuck on 3/4 and NOTHING has worked for those, but I can see into that tank and can visually see the level. The black also empties completely as I can see the bottom of the tank and it is clean as can be when we empty it. We have always used tons of water. Tomorrow I am going to try and put like 3 bags of ice in the black and if that works great, if not, not going to worry about that.

This is our 4th Motorhome and I have never had my sensors not work so it is frustrating.



Thanks