Review on Ade Advanced Optics Dual Scale Salinity Refractometer (1.0-1.070 S.G.) for Aquariums & Seawater by Charles Barney

Tested today and found it reads RO/DI water accurately at 1,000 so it was good. Since no instructions were included, I turned to the forums for usage/size details. This led me to realize that this is actually a SALINITY refractometer as stated in the description but slightly different than the SEAWATER refractometer. This introduces a slight error in the actual seawater reading, as this really only applies to sodium chloride solutions. This can be corrected by calibrating it with a solution of known salinity, making it accurate at mid-scale (where the salinity of your seawater would be). I'm not sure if links are allowed in reviews, but I'll try to show my links: [.] DOT org/forums/topic/46729-if-youuse-a-refractometer-you-should-read-this/ [.] DOT com/issues/2006-12/rhf/index.php #15 I ordered the calibration solution recommended in the second link (also from Amazon) so I don't have to worry about my seawater accuracy. Calibration solution: B0057IN2SW