If like mine, the entire underneath is exposed.
Should be able to unscrew the crossbars that hold the tank in, tip it slightly and let it down from the camper.......from what I've seen on mine. Of course, disconnect the water level sensors and plumbing hoses.
2012 Fun Finder XT 276 Toy Hauler & Harley Davidson Ultra Classic with Condor wheel chock
2014 Dodge Ram 2500 AT 4X4 Crew Cab 6.4 L Hemi, 373 gears, tow package, Rambox option, Revolver X2 tonneau cover, Equal-I-zer anti-sway hitch.