Charlie,
Welcome to the forum. Post a snapshot of what you are seeing on your screen so we can see what you are getting right now.
The tilt of the transducer can affect how the arches appear. If the arches are not symetrical on each side, your transdcuer may be tilted forward or backward a little.
If you have a lot of clutter, you probably have Switchfire set to MAX mode. Turn it OFF and see what happens.
Post some images if you can. This will be the best way for us to see whats really going on.
Hope that helps.
Robert