HOW TO USE A SALOMETER
A salometer is a hydrometer that measures the density of a sodium chloride brine using a scale marked
for percent of saturation, 0°S to 100°S. A 70°S brine, for example, is 70% of fully saturated brine, which at
60°F would contain 1.75 lbs. of NaCl/gallon with a specific gravity of 1.139.
There are different types of salometer scales. Some are based on a different saturation point, with 100°S
representing 25% NaCl rather than 26.4%. Most are calibrated at 60°F but some are intended for cooler
temperatures such as 38°F.
Proper procedure for taking a salometer reading are:
1. Start with a clean, straight-walled glass cylinder with a diameter at least twice that of the
salometer bulb with sufficient height to allow for complete immersion of the salometer scale.
The cylinder should be tall enough to allow the salometer to float at a 0°S reading.
2. Place the cylinder on a level surface and fill with a sufficient volume of brine to raise the
liquid level near the top of the cylinder after the salometer is immersed.
3. Record the brine temperature. If significantly different than 60°F, a temperature correction
to the reading will be necessary (see chart).
4. Carefully immerse a clean, dry salometer in the brine. Assure that the salometer is floating
and not touching the cylinder walls. After the salometer has stabilized, take a reading at the
brine surface at eye level at the bottom of the meniscus, the concavity formed on the cylinder
walls at the brine surface (see appendix B for diagram).
5. Check new salometers by first placing them in clear water, where the reading should be
nearly 0°S at 60°F. Empty the cylinder, rinse it with saturated salt solution and then refill
with saturated brine at 60°F. The reading should be near 100°S and not less than 98°S.
When sodium chloride brines are tested at temperatures other than 60°F (15.5°C), the recorded correc-
tions in the chart below should be applied to readings before entering the salometer chart (opposite
page). Extrapolate correction values for intermediate salometer readings and temperatures.
Salometer Correction (0S)* Variation of Solubility
Temperature of Brine NaCI Saturation
00 F 200 F 400 F 600 F 800 F 1000 F Temp % Wt.
Salometer 0 0 0 0 0 0 0 0
-18 C -7 C 4 C 15.5 C 27 C 38 C F ( C) Brine
1000 - 7.2 - 4.8 - 2.4 0 + 2.7 + 5.4 0 (-18) 313 23.83
800 - 6.7 - 4.5 - 2.2 0 + 2.6 + 5.1 21 (0) 356 26.30
600 - - 4.1 - 2.0 0 + 2.4 + 4.7 40 (4) 357 26.33
400 - - 3.5 - 1.7 0 + 2.1 + 4.1 60 (15.5) 359 26.40
200 - - 2.6 - 1.3 0 + 1.6 + 3.3 80 (27) 361 26.67
00 - - + 1.0 0 + 1.2 + 2.4 100 (38) 364 26.68
*Below 60 F, subtract correction from salometer reading.
Above 600 F, add correction to salometer reading.
Orders or questions? Call (800) 241-7951 or (706) 864-3773 | www.polyportables.com