30 gallon enosure

[nikkubus]

I would put the heat mat on the hot end set to 90 or just above by placing the thermostat probe on the heat mat, and then checking what the temp is inside the enclosure under the substrate. You want it no more than 90 inside.

I would put the CHE near the center, but slightly towards the hot end, set to 84F ambient under it about an inch above substrate and see what temps you get ambient in the hot and cool side. Your ambient shouldn't be 88-90, that's too hot. If the cool side is still under 78, I would slowly move the CHE towards the cold side while turning it down a tad. If the cool side is above 82, I would just turn it down a bit. Any adjustments or movement of the CHE should be done after several hours, as it takes quite some time for everything to stabilize.

If the snake is already in this enclosure, I would start the CHE dimmed to just barely on and slowly turn it up after several hours as needed. Too hot will cause problems a lot faster than too cold.

CHE is not ideal, and if you have the money, RHP (radiant heat panel) is a better choice for ball pythons. It will dry the air a lot less, and won't cause heat spikes like a CHE that is too high wattage will. A dimmer is better than nothing, but as your house ambient changes, it will change how hot the CHE is actually making your enclosure, and is not ideal either. A pulse proportional thermostat is a better way to regulate a CHE that can adjust as needed when you house temp changes.