Interference from prop wash

Hi guys,

Boat: 2017 GW 330 Express, twin yam 350s
Equipment: ES127s, M265 in hull TD
Install location: mid-boat center, aft bilge compartment under aft cabin

Issue:

Machine works great on plane, trolling speeds and holding bottom.

Reverse throttle low RPM creates prop wash noise causing lost bottom on the fish finder that tends to linger well after wash has dissipated.

I am looking for the solution to 'reset' the FF to accurately find the bottom again without powering down units. Is there an easier method than system reboot?

Thanks!

Sean