How to ensure that the 5 gallon bucket has been washed clean?

Sheenstar 5 gallon inside washing machine have 26 flushing stations. During the inside washing process, the machine equipped with five water storage tanks.
First step: Rinse with cold pure water
Second step: Rinse with hot pure water
Third step: Rinse with disinfectant water
Fourth step: Rinse with cold pure water
Fifth step: Ozone water flushing
After the 26 flushing stations 5 step rinsing the clean 5 gallon barrel will go to the 5 gallon water filling machine.