Good Sam RV Club Member
We have a similar or exact problem.
I use a shot five foot sewer hose, from the tank connector, through the hole. When collapsed,with the trap door, in floor, cap on it and after thorough tank rinsing, there are no odors.
It is constructed like the Rhino but has red fittings.
The Rhino up through the hole and contorting it to make it connect had me concerned about strain on tank. The connectors are too long. I've tried the clear 90 degree elbows but the lugs are out, of place and it is just as long and won't work. A water tight swiveling 90 degree with shot extension and another 90 degree right over the trap door would be nice.