80 shouldn't be a problem -- I like having a hotspot at one end so there is a gradient from 85 at one end to about 65 on the other. I looked after a Red-bellied Snake that would sometimes regurgitate worms but ate slugs just fine. She was eventually moved off of slugs but for some reason she just seemed to handle them better... If all else fails and your snake still isn't keeping worms down, you might see if it will eat a slug. We would have just kept the Red-belly on slugs but up here during the winter it would become a challenge...