Caution for anyone using a refractometer

[Delphinus]

Uh .. ok, not having read Randy's article for now, but having followed the other link ..

Isn't that calibration fluid intended for the electronic salinity monitor? In that case it makes sense to me that it's using a saltwater based reference because it's using a relationship from conductivity to relate back to salinity.

Whereas a hydrometer being a mechanical device where you just look through it, I think you may still want to use RO/DI as your 1.000 reference ...... just my $0.02, I'll try reading the RHF article later when my brain is less tired..