Hard Water

[mesenteria]

There is a lot of gallons in $800

Quite so.  Still, a person should not drink softened water if possible, if that's what they use, especially those with high BP; there's still some sodium in softened water, although it's acceptable with typical hardness levels in urban areas.  Really hard water will have close to 100 mg/l of sodium after softening, or even double that amount.

If the taste is objectionable and they don't like to have to descale kettles by using water straight from the well, an RO system would really help.  An RO system effectively distills the water, or equivalent.  They would be drinking many times each day what the CPAP machine needs for their therapy, so that $800 would pay for itself within a couple of years.

https://www.drweil.com/health-wellness/b...ned-water/

[CZOscar]

I always use distilled water at home but was on a short 2 nights business trip last week and opted to use bottled water on first night and still had some after first night so topped off with tap water for my last night.

Was absolutely surprised to find crusty minerals on bottom of humidifier after my second night.  

It cleaned up easily with vinegar when I got home but I will be more cautious on what water I use when on travel.