endless, are you fishing waters that will develope a thermocline?
The Fishmark 320 I used to have would show a thermocline with just the automatic sensitivity setting. I never had to adjust the sensitivity for it.
Actually to get a positive identy of a thermocline you need to check the water temp at the level the units indicates there may be one. There is plankton in the water that will look like a thermocline on a LRC display this time of year. If you are on the water all day, that return will change depths unlike the actual thermocline which will be at a constant depth.
I don't have a Lowrance screen shot of a thermocline, but this is a Humminbird color display of one last summer: