If you switch over to The Master Cleanse you'll be interrupting the water fast.
Basically it would gently break the fast. The Master Cleanse being pretty much a juice fast.
Also to get the most out of a water fast, plenty of rest is needed.
The conserved energy is used by the body to do the work that it does during a fast.
Here's an outline of what occurs. //www.curezone.org/faq/q.asp?a=25,1787,2836&q=759
At 14 days you should be getting into some really great benefits at this point.