How long does a tainted fuel tank stay tainted?

Question

(tainted with red diesel)

Answer 1

It depends on how much diesel is in the tank it will stay tainted until all contamination is burned out of it. You will know it is all cleared out when the engine stops running a little rough. If there is too much red diesel in the tank the engine won't start and you will have to drain all fuel out of the tank and lines.

Answer 2

at least five tanks of full fuel