D-D seawater refractometer

pegasus

Well-Known Member
I'm a bit slow sometimes, which explains why I've just learned about the "seawater refractometer" from D-D. Here's a little info that I found very interesting:

"Specifically designed for aquarium use for measuring the salinity of Natural Sea Water.
Almost all hand held salt water refractometers available to the hobby are designed and calibrated for the testing of brine solutions, i.e. sodium chloride, and are not calibrated for the refractive index of natural sea water.
Even though the largest percentage of salt in the sea is sodium chloride, the presence of other significant ions such as magnesium and calcium in natural sea water results in a different refractive index relative to that of brine. A standard salt (brine) refractometer will therefore not give the correct salinity for natural sea water (NSW) and a conversion factor must be applied.
For example a 35ppt solution of NSW has the same refractive index as a 36.5ppt solution of brine. When using a normal brine refractometer the user should therefore look for a reading of 36.5ppt when trying to achieve a reading of 35ppt for natural sea water.
EASIER TO READ
One of the other problems with most refractometers is that the scale displayed normally reads from 0-100ppt when we are really only interested in the region from 30-40ppt.
Our new Seawater Refractometer has therefore been specifically designed to read from 0-40ppt which gives you 2.5 times the resolution of a normal 0-100 scale."

You can read more about it here: http://www.theaquariumsolution.com/files/SEAWATER REFRACTOMETER V2.pdf

I think it's time for an upgrade...
 
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