Dry enclosure even when misting routinely

I have a problem with humidity being bone dry in my vinegaroons enclosure. I mist the enclosure every day in the morning and usually again at night when I get home. This is around 13 hours apart when I mist x2 a day. I've gone through 3 different types of misting devices and the ones I've had have either been leaky at the nozzel or the pump itself breaks so part of me thinks it's that. I think some of it may also be the mixture I made for the substrate in the enclosure. The moisture never really penetrates any of the substrate and instead almost sits on top of it. What do you use for your substrate? I used a mix of eco earth, sphagnum moss, and peat moss when i made the enclosure. What else can I do to keep it from getting so dry? I live in a dessert climate, the actual native habitat (NM, USA) for my vinegaroon, so I don't know if it's okay or not that it is so dry. It just makes me nervous, especially when she could be molting at this time of year.