@lizzie and @JSHarris to be absolutely fair to Halcyan:
Their marcomm uses a different definition of "soft" to Jeremy's. Whether or not you agree, that's presumably a position they think they can defend under UK law and regulatory practice.
If you dig down far enough into their website, there's a white paper that clearly admits they don't know how it works. Hence, presumably, the pseudo-scientific arm-wavery.
Now, neither of those points lets me forgive the company for spamming this group with pseudo-science. But I'm perfectly willing to believe that it does do a similar job as phosphate dosing (but somehow using metal discs instead dosing with phosphate).
In other words, Liz says it seems to precipitate out the calcium in a way that doesn't stick, just like my Combimate does. And that's cool.