There are some things you can do to set up your HDS units to perform optimally.
First, with the unit on, hit menu twice, go to Soar and hit enter. In this menu that comes up there are two things you will need to set, Fishing Mode and at the bottom, Installation.
Go down to Fishing Mode and hit enter. General use is the default setting dictates that the sonar will search from 0 to 2000 feet of dense water, like salt water. If you are a fresh water fisherman, choose either Fresh Water or Shallow Water. Fresh water will search from 0 to 400 feet, like trolling deep for kokanee. Shallow water is the most common setting for typical bass fishing, it searches from 0 to 100 feet. Choose the one that is right for you and hit enter.
Now go down to Installation and hit enter. Look at the bottom of this menu and look for Transducer Type. It will say "unknown" from the factory. Use the arrow keys to move the blue box down to Transducer Type and hit enter. The list of transducers that Lowrance makes comes up. Now look at the transducer cable that is plugged into the back of the unit. Find the chrome tag and locate the model number of the transducer you are using for that unit. Find that model number on the list, arrow down to it and hit enter. Be sure to hit Save.
Next hit Pages and go to the Sonar screen. When in the Sonar screen hit menu once and go down to Ping Speed. Use the arrow keys to change the default setting of 15 up to 18. This will help the Broadband Sonar show the bottom and suspended objects better.
These settings are a great place to start and as you learn your HDS menus and different looks, experiment with other settings and find the subtle settings that may help you. If you have any other questions as you use your new HDS units please come here and ask anytime. I will do my best to help you get the most out of these great units.
BTW, if you have any questions about the GPS as you experiment with it ask those questions here also and I'm here to help.