OK.

Bottom line: I do not know how it works, or if it works. My STRONG suspicion is that it has ZERO effect on the calcium in your pool.

In fact, if you can come up with some way to TEST whether it works or not (that we can agree measures fairly), I'll bet $100 to your $1, that it does not work.

The copy reads just like the magnets they used to sell to do similar things, and as far as I know, there has never been ANY evidence that they did anything useful, EITHER. At least part of the description above, is chemistry bunkum:
break down the calcium bicarbonate and magnesium bicarbonate crystals and change them into a powder form (carbonate)
That quote is not just wrong, it's stupid. Calcium bicarbonate is extremely soluble, but even more importantly, does not exist in solid form, much less as crystals! Magnesium carbonate -- to get magnesium bicarbonate, you have to dissolve, and then acidify magnesium carbonate -- is just chalk, and not very prone to forming "crystals". And to say that "carbonate" = "powder form" is simply nonsense, sort of like saying that "water" = "heavy" or "iron" = "yellow".

But, I've invited Chem_Geek and Waterbear to weigh in with their reactions.

Links:
http://en.wikipedia.org/wiki/Calcium_bicarbonate
http://en.wikipedia.org/wiki/Magnesium_carbonate