I have read a lot of instructions for different Liver Flushes but don't recall ever reading anything about adding bleach to the oil and grapefruit juice mixture. I certainly wouldn't ingest bleach. Ugh.
Just go with the olive oil and grapefruit juice alone.
And yes, you can just fast the day you do the flush - but make sure you drink enough liquids. i think Julia Chang suggests just apple juice the day of the cleanse.