Glad to hear you tracked it down. Mine was off when I got it from shipping. Even off from calibration fluid so I got a different bottle and also made my own fluid from a formula on here and finally got it calibrated.Just wanted to say thanks for taking time to truly help me out. So I got my refractometer today and my salinity was 1.030 I double checked calibration, re checked and same result. So ive slowly started pulling water and replacing with RO/DI, hopefully get things back in the right direction. Thanks again for your help!