I read on a blog a while ago that tested water for tea, and we know that soft water is good for green teas and hard water is good for oolongs. it suggested that gypsum powder can be used to make a particular water harder. I was wondering if anyone has experimented with fine-tuning water for specific teas. Another thing on my mind is how the presence of minerals affects how tea tastes. Distilled water can make a tea taste flat and insipid, so what minerals can bring out the most in a tea's flavor?