i have a three year old eagle deepfinder 320.and the only way to see thermoclines is to run in manual mode.i also change the power setting once I'm in 70ft plus. when fishing in 130-200ft,and if not fishing the bottom,you can also set your depth range,say fish is running 100ft or less,set your depth at 100ft,this allows for a larger area to be seen,as your only showing 1ft to 100ft range.on smaller screen units like mine this works best for me. i had trouble with this unit not showing Arch's,and eagle finally sent me another unit,past warranty,and still stood behind it.It took some emails but they did stand behind it,Jim