Refractometer calibration.

[c.rob]

I have been reading latley that you should only calibrate with a saline solution close to what sea salt measures.
If your meter doesn't read correct salinity from 0 then how could it ever be correct? How can you be sure that the calibration fluid is correct to start with ?

I am using a Sybon model that came with pure water for testing.

 

[barbra]

My unit is calibrated with distilled water, not salt. How could it work with salt? Don't you need to know the starting point in order to make a determination? Don't you need a refractometer to test the water you are using to calibrate with? How do you calibrate your calibrator then? This is a vicious circle.

 

[mstewart]

Here is the best article on calibration and the different types of errors inherent in refractometers

Refractometers and Salinity Measurements

Bottom line is that most of our refractometers are better when calibrated with a standard 35ppt saline solution despite the instructions that they came with. The article gives several methods by which to accomplish this.