Milwaukee MA887 Calibration

[Solo McReefer]

Does anyone know how to calibrate the Milwaukee MA887 refractometer?

I re-zeroed it using the steamed distilled reference 0 PPT water. now it's reading 4 PPT higher than it should. PIA. I can't find it in the instructions or on YouTube videos

They all discuss zeroing the equipment, not calibration. Those are not the same thing

 

[drolmaeye]

I have/use the same digital refractometer. AFAIK, the zeroing process using pure water is the only way a user can configure/prepare the instrument for accurate readings. There is not a separate calibration process that can be done by the end-user.

I have compared my MA887 against my Tropic Marin precision hydrometer multiple times and found that when my hydrometer indicated a specific gravity between 1.026 and 1.027 (my target) in my tank, the Milwaukee refractometer would read 36 ppt (instead of 35). So I just use 36 as my mixing/testing target. Your unit may be slightly different based on the factory calibration, so worth double-checking against some other method from time to time.