Originally Posted by Radio
Here's a guy that put together a series of test for various gadgets that rinse your black tank.
Runs a bit long but clearly shows how well (or not) your tank is getting clean.
Great info, but I think the guy was a bit reluctant to really say that the Sewer Solution, RV Hydro Flush, and the Flush King all do a terrible
job of rinsing the tank. They do pretty darned good at cleaning the piping close to the device, but that's it.
I had a Sewer Solution years ago. It's great for unusual dumping situations like up hill or long runs because it is first and foremost, a water driven pumping system and it pulverizes the larger "chunks" meaning that a 1" hose can be used instead of the traditional 3" sewer hose. The downside it that it uses a lot of water. At the time we were living in a home with a low production well. Not a good combination. The early models all had plastic issues and broke in just a season or two. I noticed the one in the video is much different in that regard.
The in-tank pressure rinse systems like the Tornado do a much better job of cleaning the walls, and depending on the direction of the pressurized water flow, can work pretty well on the stuff on the floor of the tank. My Cougar (by Keystone) has a factory installed spray system, again powered by water, but it seems to move up and down or side to side with a flat spray pattern. It seems to work as least as well as the Tornado. And, like in the video, I learned early on that ignoring the manufacturer's instruction and closing up the gate valve for a minute or two with the spray running does an even better job of cleaning out the tank.
When I am finished camping, I dump at the campground before heading home. I then charge the black and gray tanks with at least 10 gallons each of water. They're each 38 gallon tanks. Then we head home. The movement of the trailer on the road causes the water to slosh around a lot which helps break up stuff that might be left. I dump when we get home, and for the most part, there's very little solid stuff visible in the dump pipe. It's got a rich color to it, but it runs clear with a flush after dumping.
My down pipe from the toilet into the black tank is a straight shot so I can see the floor of the tank. After cleaning, it's just plain shiny wet black ABS with no sign of any material. That also lets me use one of the spray wands which also helps clean the walls and ceiling of the tank.
We all put a lot of thought and effort into cleaning our black tanks, but the grey tanks get little consideration. That's why I charge them with water just like the black tank. On my last trip home for the season, I pour a half cup of dishwashing detergent into each tank along with the water. I don't have much hard evidence, but the water runs clear after flushing at home, and the tanks don't smell bad. I'm content with those results.