I've had the same problem with my tanks as well. Idk what type of substrate you're using but if you aren't using something like coco husk or reptibark or something of that nature that home humidity well that will help.
Sphagnum moss is also awesome for keeping up humidity, and pretty cheap too. I take a bit and mix it in with the substrate when I clean the tank and also line the back and sides of the tank with it like a hedge or something XD When you spray naturally the moss in the substrate will help them I just spray the moss along the walls directly and wet them real good.
Another trick I learned on here is get a cheap dish rag or wash cloth, set them down (Not like soaked just wet, you don't want it dripping) and place it on top the the hides. When they shed I put one on each hide to bring up the humidity more but normally I just leave one on the hot side hide and that's enough for mine. I usually take out the rag every other day or so when it needs it and rewet it but other then that I just spray it directly like I do with the moss and that's good.
With all this I normally just spray the tank once a day and they do just fine. I hope this helps!
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