In article , John Connett scribeth thus
The mains water supplied in Cambridge is hard. The Cambridge Water
>hardness report gives 323 ppm for the calcium carbonate equivalent for
>North Cambridge and 315 ppm for South Cambridge. My new heating system
>will deliver mains pressure hot water via a plate heat exchanger and I
>am contemplating specifying a scale reducer or inhibitor. There appear
>to be three main types: chemical (polyphosphate); magnetic; and
>electronic. I'm prepared to accept that the polyphosphate type might
>work (but then I haven't studied chemistry since secondary school) but
>the magnetic and electronic types sound rather magical!
>
>Any recommendations?
Shouldn't need one. I've have to cover the maintenance on a few properties and have never had a problem as such with the water hardness..