I have a refractometer. I use it to calibrate my Sea Test Hydrometer. I have found that my hydrometer is out by .03! So, when I use it on a day to day basis i just add .03 to it and it's corrected. The real key is having the consistient salinity. That includes same salinity in the tank and water change salinity.
I re-test my hydrometer every time I do a water change just to make sure it holds.
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|NAS- If it's not broke, don't fix it.
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