Pointless and no worky!
There was an electronic one in my flat, rubbish.
In the house we installed a electrolytic / magnetic type, crap!
So now I have put in plumbing with the option for fit salt softener. They are a few £'00 and coat £60 per annum to run I think. So, we are undecided.
I have 1 loo I need to re-plumb so that is is on the softener and then only outdoor taps, kitchen cold and bathroom colds are mains direct.