Specific gravity testing

[orca67]

I just picked up a refractometer off ebay $40 only problem is it only has a percentage scale on it anyone know how to cross over SP to a percentage I think that 35,000 ppm is 3.5%

 

[cmor1701d]

What kind of refractometer did you get?
Are you sure it is meant for salinity? It might be a Brix refractometer meant for alcoholic beverages. You can google a conversion table to SG, though I'm not sure it's equivalent to the SG of salt water. Assuming that SG is just the amount of solids in pure water, then I guess the conversion table would be the same.

 

[orca67]

Not sure of the name brand of it. The case says Salinity 0-28%. Operation manual says it is used for testing salt water ppt. I will check out net some more for a coversion chart. Thanks

 

[cmor1701d]

So ppt or 35ppt = 1.026 SG. You want to be in the 34 - 36 ppt range for a reef.

There's a great article on Refractometers and Salinity Measurement, but the chart doesn't go down to Hypo levels.

Any chance of returning it for a different model?