Re: Tea with milk
Hard/soft water seems to make a difference to taste and to colour. Tea acts as an indicator and it's difficult to judge its strength in hard water areas.
I was spoiled for several years in London by having an ion exchange softener on the mains. Still needed a Brita filter to make decent tea, and you're really meant to have an additional exchanger on the drinking water, so the extra Na probably didn't do my blood pressure any good.
No longer have that, so have now developed a two step filter involving two filter jugs, one Brita, one BWT. (Some testing indicates Brita-Brita would work, but arrived at this stage by getting the BWT, deciding it was an improvement over the Brita, if not perfect, and then realising I now had two filters.)