This is something I've done on a few 20 Gal long tanks. Just thought I'd share a sketch.
This is the easiest way I could come up with to have a varied average temperature from one side to the other, and front to back.
Prior to this, I had one strip of Flexwatt at one temperature, and another strip at a lower temperature. With the heat cable trace above I was able to get a similar effect with a single heater and controller.
Obviously you tweak the layout for your animal and background temperature. This layout is for a spotted python cage in an unheated room hence the larger percentage of heated floor area.

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Mark


