We have a 2016 191RDXL with one trip on it ( besides the trip back to the factory but that's another story) water tank has been empty since that trip in April. Filled the tank last week due to fire evacuation orders. after filling and doing the final walk and inspection I noticed the rear support strap for the water tank was bowed about 3 inches downward. so I just drained the tank.Now that the fire is contained and I can crawl under the trailer, the tank should be empty? but I got at least 10 gallons out of the tank and it still is sagging. I removed the black plastic panel from below the tank and the sag is evident with the tank empty or full. when full the tank also bulges upward and pushes against the floor. I did check the vent line and it is not trapped and bleeds water when the tank is full.
sorry for the long post : now the questions
1. What is the purpose of the black plastic panel, Can I safely leave it out?
2 is this much tank deformation normal?