How are you increasing humidity? I found that If you use a humid hide it provides sustainable levels of humidity without everything having to be drenched. I use tupper ware containers, and cut out a portion just large enough for the snake to enter and exit through. Put a handful of sphagnum moss in the container, soak with warm water, drain water, and attach lid. Turn upside down and put in tub or cage. This provides not only humidity within the hide, but over time slowly releases moisture into the ambient air in the tub. You would be surprised how humid you can make a tub without having to see condensation. Once you see small amounts of condensation you are achieving 100% humidity, which is unnecessary for most Boas. For larger animals you can fill a container with sphagnum moss and punch holes in it to allow the moisture to release, yet keep water and damp moss from spreading in the tub.