Salt-water flushes are considered dangerous by some because of the sudden influx of high concentrations of sodium, and this could be esp' so on a water fast.
The bowels and colon, which for the most part shut-down on a fast, should take care of themselves post fast, if the diet is wholesome and plant-based.
"In evaluating claims for flushes and other cleansing regimes, be aware that the body does a pretty good job of cleansing and purifying itself. If you focus on good nutrition, regular exercise, and other healthy habits, you won't feel the need to do this sort of thing"..........Dr Andrew Weil MD.......on Salt-water-flushes. http://www.drweil.com/drw/u/QAA400277/sea-salt-flush