During a recent pre-flight check my fresh water tank read 2/3 full. It had read 1/3 earlier in the trip and I had hooked up to city water on the stay. I figured I had inadvertantly added water, so I dumped water until it read 1/3 again.

During the trip back I used the head and flushed accordingly. When I got home (about two hours later) I heard the water pump running and found that the fresh water level was empty (as well as no reading on the black water as it was empty as it should have been, save the one use). The water pump was very hot so I can see a new one in my not too distant future. I should have shut the water pump off after using it, which I normally do but didn't this particular time (fate is my buddy).

Not sure of the technology used to measure the tank levels, I suspect that it is not all that accurate and can be fooled by some kinds of circumstances. Is there someone that can educate me on this issue?

Look in the owners manual for the tank monitor calibration procedure. I have to calibrate mine every time I dump or empty the water tank. My system uses pressure sensors in the bottom of the tanks to report to the Aladdin system what the level is in the tanks. If yours is a different system then I can't do much for you. Have you tried calling tech support?