Neither is actually required (according to the book) I like using both because I get better results from my SWF. I see the tea like my internal car wash and the SWF (Salt-Water-Flush) is the rinse cycle. Even if I use tea morning and night I don't feel like I expelled as much.
The tea does take some getting use to. I had to start by steeping it less and tried a few types for taste. Now it is a comfortable part of my evening fast routine.