For over five years, I have washed my hair with well water. Prior to that, I had city water and my hair was ashy blonde. Since washing with well water my hair has turned remarkably darker and brassy.  I pondered whether it was my hair turning naturally darker or if it was the iron clad water. I highlighted my hair over the last few years and the result would be the same, gradually my hair would darken again. Finally, after desperation and wanting my newly colored hair to stay the color I wanted, I tried Malibu C Hard Water Wellness Kit. Since then, my hair has not darkened and is still the blonde I colored it. Finally, my hair is the color I want it to be and it lasts. Thank you for a wonderful product!!