The Hach reagent (the test kit in the video) is intended to be used with a "Water sample". Not a solution of a caustic in water!! Are there any instructions provided with the test kit that may indicate of the possible interferences, when we use that kit, with solutions other than water? IE:NaoH or KOH in water!! Water is not a solution on it's own!
Note that the color did not match any of the reference colors.
The caustic in the water is causing interference with the test colors.
These test kits are specific to the sample medium
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