Tank2379
Active member
If anyone has a Hydrometer you can also check you calibration with that compared to your refractometer normally they match up or close to your water salinilty. Hydrometer are pretty accurate themselves this is how I test if my refractometer is out of whack. I use RO/DI and believe it or not Marine depot advises on using RO/DI on there refractomoeter becasue that is how they design them to be calibrated at least when I had a problem with mine I told them I used Calibration fluid they stated not to becasue it throws off the calibration. This is if you are using a Marine Depot brand refractometer. I would really suggest asking the manufacturer what is the best way to calibrate them...... Most migh say just RO/DI and some will say calibration fluid... But this is just what I have experienced with my situation..