I replaced the gauge in the galley as my first attemp to fix the problem. Unfortunately, the problem is likely the sender unit on the actual port tank. After communicating with another owner about the difficulty in accessing the port freshwater tank under the galley floor, I followed his solution and just ordered a Jakmeter (http://www.jakmeter.com/
) which I will install next to the freshwater pump. The only draw back is that I need to reset the meter each time a fill the tanks.