Welcome to the forums,

Bloods handle humidity really well really well, and need it to survive with out health problems. My blood is in a Animal Plastics T3 enclosure with a constant humidity of 82-85% that I maintain by keeping a water bowl on the hot side of the enclosure that evaporates to fill the air with moisture. Prior to moving him into this enclosure he was in a large rubbermaid box as his enclosure and had a bowl of damp moss to crawl into and a water bowl for soaking/drinking.