Take Auto sensitivity off first.. With freshwater lenses, algae blooms, etc that we find in our local waters, auto sensitivity is a surefire way to loose bottom. Then make sure you've set ping speed to max, set to "General Use" (freshwater, saltwater, slow trolling etc are all garbage). Now reduce sensitivity until the screen clears up, then bring it back up to the point that it just starts to clutter up again. Are you fishing in the Alberni Canal? Often with the amount of traffic there, your sounder will get confused with all of the other sonar signals bouncing off the walls.. the only solution is another frequency or a way more powerful transducer... a lot of guys running the 1000w transducers there, knowing their signals will mess up everyone around them..