In my 10gallons i have one per tank and anything more than that has one in the hot and cold side. A simple way to get a reading is with a dehumidifier.
As long as you provide it the proper hydration with good water bowls and a constant supply of fresh drinking water your pet ball python should have the moisture levels it requires to be happy.
How to get humidity down in ball python tank. The sides of the water dish should be low i just got a brand new. Pet ball pythons also need the right thermal gradient with a cool spot at one end and a hot spot at the other. Cut a hole in the lid and put in damp paper towel to make a cheap humidity box.
Ball pythons thrive at humidity levels of 50 60. An indicator that all is well with your ball python is his shedding habits. Also dry bathing your snake in lukewarm water for 15 minutes a day.
Since most rooms are 20 30 you need to do some work by including a water dish spraying down if needed storing the tank in the proper place and buying humidity raising devices. The ball python s tank should have a relative humidity of 50 60. But if you wanna get some bonus humidity holding goodness in there i recommend getting a small fistful if sphagnum moss getting it a little damp put it in water and squeeze it really good so it s damp but not dripping and mixing it into the substrate.
This will help your ball python separate the old outer layer of skin and will also help avoid such problems as retained eye caps.