Apparently the claim is that the ocean water has all the minerals required by the body in the perfect proportions, and plants grown in this medium will have significant mineral content compared to those that are not. I am not able to measure this claim myself, but it does make sense. It would make wheatgrass juice a superior health supplement.
As to your Buddha, I am not too familiar with religions, but perhaps you have a yogi instead. The Buddha has a tummy large enough to rub. Sure you might think you are bone thin, but I was looking at some pictures of workers from around the early 1900's and these were tough guys I'm sure but from looking at their faces and clothing most of them would be considered as starving thin in today's society. I doubt that they were juicers though.