Refractometer Calibration - Solution

[RaymondL]

I've decided to have a fish only tank, and it's mentioned that I can run the tank at 1.020ppt. I have refractometer calibration solutions commercial and homebrew (thanks Randy) which the solutions cover 35ppt up to 37ppt.

I often use a Tropic Marin floating glass hydrometer as a baseline to cross reference these solutions at the same water temperatures and the calibration solutions are accurate.

My concern is that if I use one of these calibration solutions (35ppt or 37ppt) to calibrate my refractometer, would it result in bad inaccurate readings because my Target salinity is 26.573 (1.020), and my refractometer was calibrated for a much higher reading (ie. 35ppt).

 

[blaxsun]

No. You're calibrating it to a set point for reference. If the salinity is lower than 35ppt then it will read as such on the refractometer.

 

[The_Paradox]

There is a calibration slope but you will be close enough.

 

[TokenReefer]

Calibration slope?

 

[The_Paradox]

Calibration slope?

https://reefkeeping.com/issues/2006-12/rhf/index.php

 

[TokenReefer]

https://reefkeeping.com/issues/2006-12/rhf/index.php

Ok. I see. That's referring to a type of refractometer being used and matching the calibration method appropriately. We're all in that boat. If calibrated correctly, reading a lower salinity shouldn't be an issue (far as I know)

 

[The_Paradox]

Ok. I see. That's referring to a type of refractometer being used and matching the calibration method appropriately. We're all in that boat. If calibrated correctly, reading a lower salinity shouldn't be an issue (far as I know)

For our purposes no. Will be more than close enough. If you really really want to get as close as possible though you can just make 30ppt solution.