I agree with Dale. I also installed the SeeLevel II gauges on my coach, and love them. It is nice to know that the fresh water runs out at 11%, not just sometime after the 1/4 light goes out. And after finding out just how much water siphons out, I made the modification to stop the overflow, saving a whole bunch of water.
Mine are only a few months old, so I can't tell how well they will work long term, but I can't see any reason they should not work indefinitely.
'04 Alpine Coach 36' MDDS