1.1 This test method covers the determination of soluble sulfate ions present in water or a filtrate by means of a photometer measuring the turbidity of precipitated barium sulfate. A method of standardizing the photometer for this test method is also This test method covers the procedures for determining soluble sulfate ions present in water or a filtrate using a photometer to measure the turbidity of precipitated barium sulfate. This test method also details a method for standardizing the photomet