This is such a good question and while I don’t have any ideas, I do use distilled water sometimes when my skin is really struggling. I also only wash my hair with distilled water and it makes a huge difference
I used distilled water for my face for a couple of years and I was so dried out and dull (I'm sure also not helped by using a spray on moisturizer that likely led to evaporation dehydration). I love the way saline solution feels whenever I get a new piercing, so I thought the thermal sprays might help with soothing more than distilled.