Here in Nevada, humidity is so low that it feels like 0% half the time, and the chances of not dropping to 40 to 30% are almost impossible with out a terrarium humidifier. Now, the simple fix is in the last sentence, terrarium humidifiers are expensive, so take out the word terrarium and replace it with Room. The reason your humidity plumits in the first place is because the room humidity is way to low in desert regions, so even if you get the terrarium perfect, the humidity will distribute into the rest of the room. So if you use a room humidifier (if you need to go really cheap, head over to your nearest goodwill, I got mine for 5.20 and it works perfectly) to get the room to 50 to 60% the humidity won't just stay in the enclosure, it will go into the enclosure it self, and you will just need to refill the water. Hope this helps anyone in these regions with there inedible humidity problem.
Sent from my Moto E (4) using Tapatalk