Cant Get My Tank Warm

[Homebody]

I have a 40 gallon for my ball python that is heated by a heating pad placed under the tank but I can get my surface temp to be hot enough without setting the thermostat really high. So I then went and bought a heating lamp but the the thing is it would suck all the humidity in my tank within hours. I don't know what to do. I thought maybe my heating pad or thermostat was no good or maybe even my substrate I use zoomed reptibark. What should I do?

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