Still storing my RhinoFlex in the bumper, but when I uncovered it after winter and starting getting it prepped again I found that it was very difficult to get the hose out of the bumper due to the rust build-up. It was sort of stuck - and that was after just one season of use. So I've scrubbed the inside of the bumper out with a wire brush and naval jelly to remove the rust and applied a good coat of Rustoleum. The finish is very smooth, almost like it's been waxed, and any moisture that gets inside just beads up. After each trip I pull the hose out and let it air out for a day or two.
TT: 2015 Jay Flight SLX 195RB Baja Edition
TV: 2014 RAM 1500 Bighorn CC, 5.7L Hemi, 3.21, Factory Air Suspension/Tow Pkg, Andersen WD/SC