5
Preparing the Calibration Salt Solutions
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For your first use only, you will need to add water to the provided salts to prepare the saturated salt
solutions for the calibration chambers.
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Note that it is important not to cross-contaminate either salt solution with the other salt. For this reason,
every item is color-coded. Make sure to keep red items with red, and blue with blue, throughout the
mixing and calibrating process.
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You will be mixing the salts with water. We recommend distilled water if available, but clean
uncontaminated tap water will not measurably affect the accuracy of your results.
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For both solutions, your aim is to produce a “slurry” in which you can still see visible grains of salt as well
as a small amount of liquid water above the salt.
1. Open the two labeled jars. Remove the two plastic spacer grids from the jars.
2. Open the sealed vial labeled “Sodium Chloride 74.0% (High)” and empty the salt into the bottom of the
jar with the same label.
3. Fill the small measuring cup to the RED line marked “NaCl” (13 ml.) with distilled or clean tap water.
Add to jar.
4. Using a stirring stick, stir the solution for at least a minute. Please do not shake jar to stir as this will
deposit salts on the side of the jar, affecting the overall solution. Observe the consistency. If necessary,
add a few drops of water to achieve the desired slurry consistency, and stir some more.
5. Place the lid with the same label on the jar and tighten securely.
6. Repeat for the Magnesium Chloride 32.80% (Low) solution, filling the measuring cup to the BLUE line
marked MgCl (5 ml.) and using the BLUE color-coded supplies. You may need to use a stirring stick to
scrape the salt out of the vial or bag.
