I highly recommend you attend one of Lance Valentine's seminar's on fish finders if you ever have the chance. I've used several different ones over the years starting with the paper graphs to my current Garmin color unit. Going from memory: 1) Always have fish I.D. feature turned off. 2) Don't use the auto settings. 3) Manually adjust the gain as high as you can. If you don't have some interference showing, then your gain isn't high enough. 4) Large hooks (horizontally) don't mean large fish. It just means the fish moved within the cone. 5) Thicker marks, (vertically), means bigger fish. 6) Bait fish will show up as a blob, not small hooks. 7) If you see a blob with hooks around it, it's predatory fish feeding on the bait fish. If you have a good quality fish finder with a color display, with the gain adjusted properly, you should be able to see the thermocline. What you actually see is the tiny zooplankton stuff that ends up at the thermocline. The thermocline is where there are two different densities of water that won't mix. When I first got my Garmin, it was awesome to go out in the morning, see the thermocline on your screen with a bunch of hooks just below it, drop your riggers just above, and slam the fish. What's also amazing is that once the sun comes up, the hooks disappear. Joe, "Sloppy Joe"