Thank-you thank-you thank-you! For the encouragement!
I ahve to tell you, I just bought a new juicer! It's the "Hippocrates Juicer, the next generation of Green Power Juicers (not available on the greenpower website; have to go to: http://www.hippocratesjuicer.com/
Anyway, the juice is WONDERFUL!!! I have a Juice Lady Centrifugal juicer, and it's great, but the juice from the Hippocrates Juicer is Light Years ahead in terms of flavor and longevity--lasts 3 days in the fridge!!
No, I don't work for them, but since you were mentioning about the juice and your watermelon, I thought I would chime in with what I have discovered.