I was recently gifted an older Lowrance x4 fish finding sonar.  It's from a friend of mine who decided he needed the latest and greatest on his boat and offered me the old "black and white" unit.  It works great on my canoe and has opened up my eyes on bottom depth and profile on a few of the bodies of water that i fish as well as the temp that the water is at.  I do have a question though.  Is it possible to see a thermocline on a unit such as this or is its technology old enough that I shouldn't bother?  I ask because one of the lakes i fish has a lot of water that is 30+ feet deep and I have always just excluded it thinking it would be below this line anyways and i have never caught a fish in that depth during the warm months.

I believe, someone correct me if I'm wrong but if you run the sensitivity all the way up in the 9o% it should give you the depth on the thermocline. Then just readjust it.