Originally Posted by pumper9x9
The problem with those gauges is that if the walls of the tank are fouled the gauges will stop working. So you still have the same problem. I talked to an engineer at the company not a sales guy.
This quote take from here:
"Fortunately there is a relatively simple solution. SeeLevel makes a variety of monitoring systems suitable for almost any RV, from tent trailer to luxury diesel pusher. These monitoring systems work completely different from the standard fare. Rather than using through-the-tank sensors, the SeeLevel sensors are mounted on a flexible “electronic strip” that adheres to the outside of the holding tank. They can never be fouled or contaminated as they never see the inside of the tank. Well it sees it but only though some magic radar system.
From the outside of the tank, the sensors determine the tanks level by the density difference of the liquid as measured between all the sensors on the strip. So it is highly accurate and virtually foolproof. And instead of LED lights, the monitor displays the tanks levels using a percentage, which is arguably easier to interpret than some fraction."
So it appears a little crud film on the walls of the tank will NOT have a measureable effect.
It is not using optical sensors.
Found this quote here:
"If the tank wall build-up approaches 1/2 inch thick or more with scum or debris, the system will pick up that mass as a water level—another reason to clean and flush your tanks regularly."
To me 1/2 inch thick scum seems like a lot! Not likely on an even halfway maintained black tank. So seems reasonable to say that for most RV'ers this system will work fine.