I would not use the carpet. You can not spot clean them. Which means every time the snake poops you have to either leave the carpet in there with the liquid that you couldnt clean or you have to pull the carpet every time, clean it and put it back. I personally use coconut husk bedding. Holds moisture very well without mold risk which is great for humidity. I spot clean when they poop removing the bedding from just that area and replacing with a small amout and i change the entire bedding every month or so. 55% humidity is good. Make sure the UTH is on a thermostat which im guessing it is since you said its set at 90. So other than the carpet your setup sounds A OK. Just curious did you get a morph or a normal?? And welcome to the site and to the wonderful world of ball python ownership.

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