Of course it is true!! We had a cottage in upper Michigan for generations. The water was awesome...it was sand filtered, from an underground spring. It was sooo cold, that if you were all sandy from the beach, my mom would make us take an outside shower and we would get ice cream headaches!! No smell and just the best water...we all couldn't wait to get there and drink it! We would all take as much home as we could fit, but it was never close to enough. The potatoes grew up there so much better than our home in lower Michigan..our soil was clay-ish, we lived on a river. It was hard to dig, let alone grow potatoes, but we did...just not good ones! However the solid up north was sandy, and those potatoes were so good! Plus, the plants produced triple the amounts. We are only speaking of a small distance in one state as opposed to another country, half a world away! Even the climate was different there, than my home. I hope now that I broke it down enough for you to understand the extent.