Electronics installation help

Late last season I purchased a new Onix 10 to replace a 997 SI. My 997 gave me good readings up to 25-30 mph and I had an in hull 2d transducer that could read beyond that in speed linked to my old 787 also on the dash.
I got no results at all at speed with the Onix and in fact the 787 still linked to the in hull transducer no longer gave me good readings. Readings were fine at trolling speeds.
Any thoughts on this? I hooked to power at the dash with both the Onix and 787. Should I go directly back to the battery? Fuse it there? Do I need a filter of some kind or?
Any and all help appreciated. About 4 inches of snow here in the U.P. yesterday and more on the way but I am confident Spring will come one day and I will get my boat on the water.
Thanks,
Lloyd

Definitely hard wire the units directly to the battery with fuses on the positive wire at the battery. That has nothing to do with your problem, it is just the right way to do it so you don’t have any problems with the locators shutting down at start up when the battery starts to get older. Thru hull transducers, to my knowledge, are not adjustable. Not getting good readings like you describe, sound to me like the transducer is out of adjustment