I would suggest that you get your fresh water tank supports beefed up and add some more supports as there will come a day that it will fall out (seen the FW tank fall out of one Salem and bent supports on another Salem to the point it was scary close to coming out). The fresh water tank should not 'bulge' out 'down ward'..... big red flag to do something (asap). Until you do get more (and better) supports under it, have only a few gallons in it or run it as close to empty as possible.
Is the 'breather' tube working ok?
2013 Forest River Salem Hemisphere SBT312QBUD
2001 CrewCab F-250 7.3 PowerStroke Diesel
SuperChip, BTS transmission, 6.0 Trans Cooler