I setup an account with Digitalfire and downloaded and installed Insight (level 2) and it looks like the XML file that contains recipes are no longer available.
I know water is a big component in glaze recipes and I have access to three different sources (all well water):
1) hard tap water that has a lot of calcium
2) hard tap water that has been soften using salt. According to the manufacture there is less salt in 8oz of water then there is in a slice of regular white bread.
3) tap water that has an iron content - according to the lab were I get it tested and it is potable (although I have this strange attraction to magnets )
My guess is #1 would be the best?