Usually, the DI images require a higher sensitivity setting than for SI or 2D. Turn it up a few points above mid-range and see if that improves the images. You should experiment with different settings, scroll speeds and boat speeds until you find the best images. Run over a known brush pile. When it pops up on the screen, freeze the image by pressing an arrow key. Then, while the image is frozen on the screen, mess around with the setting and see how it impacts the image. Once you git it where you like it, leave it there and go fishing!