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The specific gravity of a solution changes with temperature, so SG is usually given normalized to a reference temperature, typically 25 C for our purposes. The refractometer might be calibrated for salt, and its reference temperature for SG is unknown, so how the two scales should line up is a bit blurry.
As to why the PinPoint measures 1.025, I go back to my first statement: these devices are of variable accuracy, and I wouldn't set much store in how they measure a solution when calibrated with RO-DI water.
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Jonathan Bertoni
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