Not Joby but...

Changing the settings in the SwitchFire turn on and off additional programming that help filter some of the returned signal strength from sonar returns that are close to the transducer. It turns on and off something call time variable gain (or “TVG” the original name of this menu) which is used to try and represent the same sized sonar return for targets that are close to the transducer as would be used for the same target if it were farther away from the transducer.

The water conditions (and some menu settings) you are in will determine how shallow you can use the SwitchFire menu in the “Max Mode” versus the “Clear Mode”. If the unit will correctly track the bottom when in 2 feet of water when set to the Max Mode setting than so be it. If the unit starts having problems correctly tracking the bottom when in less than 20 feet of water when set to the Max Mode than switch it over to the Clear Mode setting.