THe seminar I recently attended they suggested that to clean sensors use a multiple step procedure
First, drain and flush the tank (In short, dump)
Then add about 1/3 tank clear water (Flush, and keep flusing, for, in my case 10-12 gallons)
Add 1/2 cup Blue (Original) DAWN dishwashing liquid.
Drive a while, oh, say 10 miles on Michigan Roads, 100 on any other states (unless, of course, your local news paper runs contests to find the worst pot holes in town, then 10 miles, ok, that's a joke,,, Drive a couple of hours)
Flush tank
Add a Waste Digester (They, of course, sold one, but you don't have to use theres)
Note: If using a waste digester DO NOT, use yellow (Antibartical) Dawn or other anti-bacterial products (What do you think does the digesting) do not use any formalhyde products.
Be aware that in some places, use of formalhyde products can earn you a date with one of the area's better known citizens. I can't tell you his full name but the traditional introduction goes something like this:
All Rise:
This session of the _____ district court of the state of _____ is now in session the Honorable Judge ____ presiding"
And he's not likely to be amused by your use of said products.
California is one such place
Turns out the sample bottle that came with the coach is such a product...I'm going to find a use for it some day, perhaps at the haz-mat dump