Hello and welcome to the forum.
It’s fine to take the probiotic with any type of antifungal. In fact, you should take a probiotic throughout your Candida treatment or indefinitely no matter what you add to your supplement list. The probiotic is the most important and beneficial supplement you will take during your treatment.
However, you may need to exchange the grapefruit seed extract for a different antifungal after you’ve been on the probiotic for a while. Candida are capable of developing a resistance to GSE after a period of time.
What is the count and number of strains in your particular probiotic? Have you experienced any of the die-off symptoms yet? You may need to read the post titled “Die-off Dangers” posted on Aug. 8.