If you are going to be removing the tank completely, that will allow for inspection of the fittings and perhaps give you a better idea of what was used in it, and if that is where the odor is really coming from. FWIW we had a SOB that had a somewhat funky odor that was coming from under the kitchen area, I orginally though it was a LP leak, but it turned out to be a critter carcase
Once it was removed and the area thoroughly scrubbed down, the odor went away. Replacement would certainly take care of most issues...
Aaron
