First thing I'd do is pull the Acu-Rite and get a read on the room your tub is in. It's a common problem that we forget to think about the room's effect on the tub or tank and that has to be taken into consideration. Snake enclosures don't live in a vacuum, they are dealing with the room around them too. Once you know what the room reads you have some idea of what it's doing to that enclosure, good or bad.

You need to watch for condensation with such high humidity readings. That will make your snake unwell, cause the substrate to become soggy and encourage mould growth.

Sometimes more holes, a change of substrate, adding a small dehumidifier or fan to a room or even moving the enclosure to another room during the humid summer months can show a marked difference.