Thanks so much for listening to the suggestions, and running this second round of tests based on the suggestions.
For the most part, your conclusions and what you found are exactly as I would expect - No matter what some folks say or what various marketing suggests, You simply can't beat a tank flusher for how well it cleans out the tank. The Flush King (or Hydro Flush with a valve) comes in a close second.
No surprise at all, that the hydro flush without a shutoff valve was useless. I figured that from the first time I looked at those devices.
I would only add the following to your conclusions:
conclusion #2: Clear section 'lying' about how clean tank really is.
Yes, when pushing water into the tank, what you see in the clear piece tells you nothing of how clean the tank itself is or is not.
HOWEVER, when draining the tank (or draining out water you pushed up in there to flush), what you see coming through that clear piece is very indicative of how clean your tank is or is not. That is where the clear piece is very useful. I have always used one for this purpose, 'cause without it, you never have any idea how clean you have got the tank.
A clear piece actually is a very useful tool for flushing/dumping, as long as you know when to pay attention to what its telling you, and when not to.
Conclusion #4: Drain-end flush systems no more effective than filling tank through other means.
Agree 100% with this. However, for those of us that:
A. Don't have a sink that plumbs into the black tank.
B. prefer to do all the flushing/draining 'activity' outside at the drain hose instead of treking in and out of the RV bathroom
C. Hate the idea of dragging a water hose and/or tank wand into the RV
..In these cases, a drain-end flush system (with a valve) is a very useful, effective way to push water back up into the tank to flush it out.
One other note: You do not have to spend the $$ for a Flush King, to get a clear piece with a valve and water line connection. Camco makes the
Dual Hydro Flush that is almost identical to the flush king - Has the clear piece, water line connection with backflow preventer and a shutoff valve to force water up into the tank, and it costs somewhat less than the flush king ($26 vs $49).
This (dual hydro flush) is what I use on our present RV, and it works great. IMO it is next best thing to a tank rinser, and these videos confirm that. I would prefer a tank rinser, but don't have one on our present RV (nor is it built to allow installing one, or I would have a long time ago). Our previous RVs all had a tank rinser, and my next one will as well.
Also, with regards to tank flushers: The tornado rinser used in this test, while it worked great here, due to its moving parts (rotating head), it is known to quit working after a while (head quit spinning, and getting jammed up as a result). The traditional 'quickie flush' units that do the same thing but don't have the rotating head, are a bit more reliable. I'd prefer one of those over the tornado flush, just 'cause that is one part that once installed, I don't ever want to have to remove or mess with again, haha. :)
