As always, the starting point is a water analysis. From there, we can find a solution to nearly any water problem. For a basic water test to get us in the ballpark, see here:
All in One Water Testing Kits for Do It Yourself water quality testing for a laboratory quality test, see here:
Professional Laboratory Testing for Water Quality Analysis
My initial guess is that you have a hard water problem, but again, a water test will tell the whole story.
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WaterFilters.NET