Im having the exact opposite problem at the moment. I just moved my snakes into plastic tubs and I cant seem to keep the humidity under 70%.
I had that problem too when switching my snakes to tubs. I fixed it by drilling more holes until I got the humidity to come down to around 50%. It was a trial and error type of thing
3.0 Normal Ball Python (Fluffy, Nado, & Muffins)
0.1 Amel Corn (Red)
1.0 Hypo Lavender Albino Ruby Eye Cal King (Vlad)
0.1 Lesser Ball Python (Sophia)