I Have my snakes on Aspen bedding and they're both in 28 qt sterilite tubs. to keep humidity up I have a large water bowl and in the corners I have sphagnum moss which I keep moist. I have to mist only twice a day, once in the morning and once before I go to bed. my levels go up to like 57-62% humidity.

I doubt scale rot would be an issue, unless you kept it soggy and didn't clean it as often.