Furuno Sounder Issue

[Venture34]

Guys - I have the Furuno Nav Net from roughly 2004. This year on my sounder the top of the water column for the top 15% of the screen is CONSTANTLY red either at speed or at rest. No gain adjustment will eliminate it. Below that blockout the sounder is working fine, picking up the bottom/fish etc. Any thoughts?

[nodoubt]

try adjusting your zero line rejection, and zero line area in your calibration in your calibration menu.....should do it....