Refractometer for Dummy (that would be me)

[the21kid]

So I got one off Ebay....the black one yada yada yada.....tried to figure it out...no luck. Can someone help me figure out what I am to be doing first and foremost...i.e. calibrating and the like. And any other helpful hints would be nice too.

Many thanks in advance

 

[loganj]

Put a few drops of distilled water on the lense, close it up, and hold it up to a bright light. Calibrate it to 0. Then, wipe the lense off and check your tank water the same way...usually takes about 4 drops of water on the lense. It should display specific gravity on one scale and salinity in ppt on the other scale. Most of us keep our SW tanks at 35ppt salinity or (I think) 1.026 SG.