V. Using the Autosalinometer to Check Data Accuracy
In order to cross-check the salinity data coming from the SEASOFT program, take samples from casts and find their salinity using the Guildline Autosalinometers located in the closet in the Bio Lab. This is often referred to as "running salts." The salinometer is a very sensitive instrument, so it is imperative to follow the guidelines below. Also, the instruction book for the instrument is located in the salinometer room and provides some more information. Please see Appendix E for notes on sampling techniques.
Occasionally, it may be necessary to use the Portasal, a portable salinometer that is easier to operate than the Autosal, but provides lower accuracy. A complete procedure is located in Appendix F. Highlighted differences between the Autosal and the Portasal are located toward the end of this section.
About the Autosalinometer
An image of the Autosal and Portasal can be found in Appendix I.
The Guildline Autosalinometer (Autosal) is very temperature sensitive. The temperature reading on the machine must be within four degrees of the room temperature (on the warmer side-the best setting is typically 24 C). The samples should be at room temperature; put them in the closet at least 12 hours before running them. The unit has an easier time warming samples than it does cooling them. Keep the door to the salinometer room closed to keep the temperature stable. If there's a problem keeping the temperature stable, close the door between the hall and the Bio Lab. Temperature control is VERY important.
It is very easy to contaminate a sample. To prevent this, wear rubber or laytex gloves, and don't touch anything that may go into the sample or the Autosal. Use a new kimwipe to wipe down the sample tube after each sample is run.
Make sure there are no bubbles in the conductivity cell. This affects readings severely.
Before running a sample, shake it very well to mix any stratified layers. Also, wipe off the mouth of the sample bottle very carefully, removing any salt crystals.

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