Caution for anyone using a refractometer

[Doo]

So after reading this I decided to get some

PINPOINT™ Salinity Calibration Fluid
53.0 mS standardized fluid for calibrating the PINPOINT Salinity Monitor™ with conversion chart

The only catch is I got it from ebay and it did not come with a conversion chart

did I even get the right stuff?

What do I do now - or how do I even use it?

Any help would be great!