I've got a Lowrance gps/fishfinder. Is there a easy way to explain how to detect the thermo-cline on my unit?

Look in the back of the manuel. My Lowrance had an example of what several things should look like and one was an example of a thermocline. If yours does not let me know. Is yours color or grayscale?

color it's a 522

Not all the units and not all the time you can see a thermocline on your sonar unit, sometimes you can se a line but not always, a shure sign of a thermocline is the way the fish icons on your screen are distributed, if you see no fish under a particular depth while you see fish icons concentrated above that depth range you can be shure there 's a thermocline.