Using Refractometer with Sodium/Chloride reading only

[serbusfish]

I just received a Refractometer and was under the impression it would use a salinity chart, however when I look through it I see this:

Can I use this to measure my salinity or should I return it and get a different one?

 

[rayjay]

Many people use them but you have to calibrate with calibration fluid of the salinity you are wanting to keep the tank at.
Calibrating with water at zero will introduce errors to your reading.

 

[serbusfish]

Many people use them but you have to calibrate with calibration fluid of the salinity you are wanting to keep the tank at.
Calibrating with water at zero will introduce errors to your reading.

OK thanks, so would this one be good:

http://m.ebay.co.uk/itm/SALIFERT-Refracto-Check-refractometer-calibration-fluid-35ppt-/261238000483

 

[andy01748]

The problem with that refractometer is you will be working at the low end of the scale and will have difficulty noticing small differences in the SG range you are interested in. For example, SG 1.025 corresponds to about 3.3%, and 1.026 to about 3.4%.

 

[bertoni]

That calibration solution would be fine. I agree that the scale on that refractometer might not be appropriate, but I am not sure what scale is is using.