[Matth]

They do work, but they don't work miracles - on the other hand, unpowered magnet ones have very little effectiveness.

The calcium is not removed, but it is altered - I did read the science once, so it does not precipitate out - this effect dissipates after some time, so it is only partially effective on storage tanked water.

I doubt that the insanely expensive units work any better than the cheap ones, though newer lower frequency units (closed coil circuit) may be better than older high frequency designs (open ended coils).

The older designs were more prone to interfere with radio.


PS. The claim of removing existing lime scale is also true, to the same extent that using the pipes in a soft water area would slowly dissolve calcium.