Salinity Measurement when Mixing Salt Water

[Jib]

Getting ready to start mixing my own salt water for the first time. Will be using Red Sea Blue Bucket. On the instructions, the last steps is to raise the water temp to 77 and check for desired salinity. The refractometer I have has "ATC" stamped on it, which I believe stands for Automatic Temperature Compensation. If it is compensating for temperature, do I really need to raise the water temp?

Thanks!

 

[Rmckoy]

IME .. I use a Hanna salinity checker but have always used a refractometer for mixing salt . I have never heated water for this exact reason .
And in Almost 20 years have never had a issue

 

[Jib]

IME .. I use a Hanna salinity checker but have always used a refractometer for mixing salt . I have never heated water for this exact reason .
And in Almost 20 years have never had a issue

Kind of what I was thinking, thanks!

 

[Randy Holmes-Farley Verified Community Expert]

Getting ready to start mixing my own salt water for the first time. Will be using Red Sea Blue Bucket. On the instructions, the last steps is to raise the water temp to 77 and check for desired salinity. The refractometer I have has "ATC" stamped on it, which I believe stands for Automatic Temperature Compensation. If it is compensating for temperature, do I really need to raise the water temp?

Thanks!

No, you do not.

 

[Jib]

No, you do not.

Thanks, Randy.

 

[Randy Holmes-Farley Verified Community Expert]

I also do not believe that a mechanical ATC refractometer needs to be calibrated at any specific temperature. Calibration at any temperature in the ATC specified range must give the same result as long as the ATC works properly.

But for reasons that I have never understood, many such refractometers specify an exact temp for calibration. I think it likely they just do not understand their own device, or just copied the procedure from another company that did not understand the principles.

 

[Jib]

I also do not believe that a mechanical ATC refractometer needs to be calibrated at any specific temperature. Calibration at any temperature in the ATC specified range must give the same result as long as the ATC works properly.

But for reasons that I have never understood, many such refractometers specify an exact temp for calibration. I think it likely they just do not understand their own device, or just copied the procedure from another company that did not understand the principles.

Very interesting, I appreciate the context!