I was asking these very same questions myself for many years, until I was finally able to heal. you don't need to get rid of candida, it is a natural part of your body, you need to just balance the overgrowth. As long as your body and immune system is getting stronger and healthy, and your diet is clean, it will get rid of the overgrowth by itself.
Before you take any Black-Walnut or other supplements, I suggest a great read from the candida experts, the same article the helped me personally heal after 20 years of suffering!
they are the first btw, that explained that there is also no need to go that low in carbs...its more important to ensure your digestion and elimination work...
Hope it helps :)