I went on Norman Walker's potassium drink for 4 months in 1976, drinking about 1 gallon every day, then continued it as part of my diet from them on.
The potassium drink consists of freshly made carrot, celery, parsley, and spinach juice. I love salads made with chopped celery, bok choy, cucumbers, and zucchini. They also juice well and also make a great veggie juice with carrots.