The speed of sound through salt water differs from the speed in fresh water.
Hydromagic supports sound velocity correction.
To enter the sound velocity for different layers of water, select "Preferences..." from the "Options" menu, and select the "Calibration" tab.
Click the "Setup..." button in the "Sound Velocity" section to configure.
More information about how to use sound velocity corrections in Hydromagic can be found in the manual.
