Hello timco, there is no reason for you to use Grapefruit Juice vs. Lemon Juice both work well
I do however suggest that you'll clear your candida first since you already began with it.
Myself, I had to stop the Liver-Flush after the 6th in order to clear the candida first because it didn't let the stones leave my gallbladder and the pressure became to much - almost to creat attacks.