We just recently got a 898 combo and since I have never used a depth finder besides a $200 2-D graph, I am learning to work it. Any tips? I have roughly figured out how to mark stuff with the GPS, but my biggest problem right now is figuring the SI feature out. I am getting there with decifering the brush, but haven't really figured out what's fish. I have researched it and they say they are white lines and dots. I saw this Friday when I went out, but it's still not totally clicking. Any advice on marking crappie in particular, and occasionally a few bass and stripers, but mainly crappie.