Nice theory wrong cause.
Tank chemicals will not address the problem the O/P sites,, IN fact they basically do nothing worthwile in most cases (IN a few cases, such as when it will be a month between dumps, BIOLOGICAL additives may help, Waste Digesters for example).
What gives one the stinky camper effect is a combination of two things.. One is required by law in some areas.
Las Vegas (I assume all of Clark County, NV) has a rule that the sewer hose (AKA Stinky Slinky) has to be in a smooth slope from RV to hole in the ground (Sewer Inlet) no dips.
Such a dip, if deep enough, would form a water trap and prevent sewer gas from backing up into the tank and out the roof vent.
SO will closing the dump valve
So a smooth slope, Such as I have just now with my SLUNKY, and an open valve (Did that by accident exactly once, in this very park) and you got the Stink-o-matic
Close the valve and the stink vanishes.
True story... Co-workers were complaining about the stench in the mens room
I dumped about a quart of water down each of the floor drains (2) and .. it vanished,, Same exact problem, the water in the traps had evaporated.