I agree that if you cannot tolerate the thought of getting something else than water into you, that you should stick to water only. Just be sure to take things very easy, in order to leave as much energy as possible for detoxing. Lying down a lot seems like a good idea to me. And do be careful with taking salt baths, because that can cause serious dizziness while water fasting.
Personally, I'm not a big fan of the acid-base approach. With situations such as chronic fatigue, I believe that it's very important that you should not only clean up your diet, but also do something about other toxins that are affecting you, such as in your home environment, in the cosmetic products you use, in household cleaners, etc.