I put one on the 27.1 ACE over a year ago. It really cleans out the black tank. I thought it was fairly clean using the wand but when I hooked up the flush, you wouldn't believe the stuff that came out.
Now I run the water a couple of minutes, close the tank and let it fill to about 3/4. Then pull the lever and let the water run until it is clear.
I hooked up a 90 degree elbow with a quick disconnect and have one hose dedicated for the black tank.
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