I noticed you said you dust the worms everyday. Dusting is definitely a good thing but can also be bad if they get to much. I would only dust every other day for a juvie and 2 times a week for adults. and i know a lot of people have dishes of calcium in the tank but I prefer not to, that way I can keep track of how much powder they are consuming, dont want any little crackheads running around, haha. Some people might argue with this but ive been raising leos for a while now and never had problems. and as for the eating vermiculite i would think it was to get the moisture as well. and the paper towel idea sounds like a good one.