I called the MFG and they said it is most likely the lining cracked. It is still under the MFG 2 year warranty. They directed me to a local RV warranty repair shop not too far away. I sent them the pics of the pieces I found, so I still need to follow up with them. My problem is that we leave for Pigeon Forge on Saturday and then the RV will stay at the lake for the rest of the season. I wish they was a way to get the water heater and install it myself, I have done one before. they are not that hard...
FYI, there is no leaking and it does seem to work very well... so maybe I caught it before it got too bad. Thanks to this awesome forum, I would have never tried to wash out the water heater tank without reading it here.
