My taste sense was not up to Hojo's water tests. The Shigaraki did not improve my Dan Cong when compared to Imen's expensive Chao Zhou pots, nor to the cheap Zisha pots from Zen 8 tea.
I feel that softening the water is not what is required for Dan Cong, in fact Imen has been known to recommend Harder Water, so maybe I should try the Shigaraki on something other than Dan Cong.
I have tried a local bottled water from Buxton which seems to meet Imen's requirements and it performs better (for DC) than bottled French mineral waters, but my local tap water with the Chlorine and Fluorine removed by Brita (that comes from similar geographical region to Buxton) is as good as the bottled water and gives me great results.
The Shigaraki sits waiting to find a perfect tea partner. Maybe I will try it with Sheng