What does the Deep Fill option do and when should I use it?

The Deep Fill option controls how much water is added to your wash cycle — set it to Auto for the machine to automatically determine the optimal water level, or set it to Max for the maximum allowable water level for that cycle. Higher water levels can be used to reduce the likelihood of white residue on dark clothing. It is recommended to use the Bulky Items cycle with the Deep Fill-Max option for loads where maximum water level is desired, though expect longer cycle times due to extended fill duration when using Deep Fill options other than Auto. (Page 1)