Think that both Calcium and Bicarbonates in tap water react with Starsan turning it a cloudy colour and lowering it's acidity...I've been using Tesco Ashbeck but don't like paying a few quid extra just for santising...is there a way of using tap water and getting rid of the Bicarbonates?
Agree PH is your target don't fret about the color. :)
You could boil it to drop out a large part of it if you want to.
Think I've read that cloudy Starsan mix creates a kinda slim that sticks to whatever you're sanitising.