One other comment; All "Water" is not created equal. When I was doing most of my bluing I was out in the boonies & had spring water. I simply could not get a satisfactory blue using this water. Had to buy the bottled water as used for steam irons. I have no idea what affect most "City" waters would have on the process, others can probably answer this, but may not be compatable.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra