These gauges DO work. It's a matter of how well you clean and maintain your tanks. People seem to think they don't have to put any effort into a black and gray tank other than pulling a lever to dump it!
Use plenty of water in the black tank when flushing. Not enough water and everything WILL stick to the sensors. After EVERY dump fill black tank with water and dump again. Then open gray and dump.
Gray tanks - this is not your home kitchen sink that goes out to a sewer, it's a holding tank. Do NOT put food solids or grease down an RV sink. After 3 or 4 dumps pour a lemon cleaner down the sink fill with water and dump again. Or add the lemon cleaner before each dump. I've watched my friends pour bacon grease right down the drain and then wonder why their gauges don't work. :S
IMHO, JMHO before you think a 'different' brand of gauges will solve the problem, fill both your tanks with water several times and dump. Buy a bottle of Thetford Sensor Cleaner and throw that in both tanks let it sit and dump. Now fill you tanks up with water and be amazed how all the pretty colors of your gauges light up! Then 'maintain' your tanks. :C
