Happened with my Keystone Challenger last winter in Az.Was backflushing and got called away.Sounded like a shotgun going off and shook the whole trailer.Can't remember what the tank cost around $300.00 I think and put it in myself.Lesson learned.Jim

Wow, what a mess. I have had so many friends with 5vrs and MHs have problems while back flushing that I am glad we did not purchase that option. We just fill the take from inside, holding the pedal down then dumping the clean water after each dump. We have never had a black tank problem or odor. Even better we have never backflushed into the rig.