Question on Refractor

[iloveswfish]

I bought this refractometer on Ebay and when i put the drops of water from my tank, and you look through it, what i see is something that says sodium chloride and not spicific gravity,,, is there something wrong with this meter.





The ad on Ebay reads this: Portable Marine Salinity Salt Refractometer for Fish Tank Hydrometer Tester

I did reach out to the seller but they are in another country and have not heard from them yet.

 

[saltyphish]

I know Sodium Chloride is salt. Maybe test your water with it and then have a lfs test and see if they measure the same.

 

[Randy Holmes-Farley Verified Community Expert]

Most refractometers that hobbyists use are actually brine refractometers (sodium chloride) refractometers. They need to be calibrated with a seawater standard and not RO/DI to read seawater correctly. You can either buy a standard or make one yourself if you have a scale.

What units does the refractometer read in? ppt? specific gravity?

 

[iloveswfish]

ppt

 

[Randy Holmes-Farley Verified Community Expert]

So it should be fine if you buy or make a 35 ppt seawater standard for calibration.