Hook 4 Simple Down Image Config Issue

[DogNBass]

Hi all, my first post here and a newbie question. Using a Hook 4 and the down scan page doesn't not show top of water column. Example: Range will be -20ft. to bottom. It happens in Auto Range and in selected range. My CHIRP page displays full water column as expected, e.g., -0ft. to bottom. I assume it's just a simple configuration, but I can't find it.

Thanks for any help.