Anybody that thinks they have the solution to keep sensors working properly, is proof that they are inexperienced,......have not been RVing very long.
This topic has been discussed hundreds of times, and always w/ the same conclusion,......if you want to spend 1/2 your life, and 1/2 your money on cleaning tank sensors, you might keep them working 1/2 the time. The sooner you learn and believe this the sooner you will find much better things to spend your time and money on, and the sooner you will learn that you don't need no tank sensors anyway.
Read "Redracer's post above, and just believe it !!