I've done side-by-side testing of a bunch of chemicals for Practical Sailor. Rid-x was not as impressive at controlling odor as some many others, though it did help some and could help turn the corner, I suppose. However, it is not an overnight solution as it contains bacteria, and as Rid-x states it should take 3-4 days to germinate. We found it took several days to do anything. Perhaps in large overdoes there was enough active enzyme present to do something.
Interestingly, Rid-X does not recommend the use in RVs or boats. They did not respond and I think they simply haven't chased that possibility.
From the FAQ tab:
"RID-X® has not been tested on recreational vehicles (RVs). therefore we cannot recommend using it in RVs."
I think there are better choices. I've spent enough time with poop to be pretty sure of that.
Three things I have found that help:
* Sail Delmarva: Something Free, Something Lazy
* Not using PG. Sail Delmarva: It's Always the Joker
* Flushing with enough water to clear the urine to the tank. Vinegar becomes much less necessary or unnecessary, depending on the waters, if there is no urine present. In 15 years I've never used an acid of any sort and had no build-up. Seawater flush.