I missed this post the first time around so I'm glad it popped back up.
I will be trying the "Calgon Method".
As far as a water softener for an RV. Well that's interesting. I was talking to a man staying in park in Malabar, FL that I will be moving to in a couple of weeks. He made a statement that I did not pursue with him at the time about needing a RV water softener due to the well water in the park.
My assumption was that he was using one and I would ask more questions when I got moved. So if I do learn anything about RV water softener's I will post back.