I use vermiculite and when mixing, I add water until I can grab a handful and squeeze it into clumps without water coming out. I then add water or more vermiculite if necessary until I get the mixture correct. I use 5.5 qt sterilite shoebox containers (with locking lids) and once I have the vermiculite and eggs in the container, I put a sheet of cling wrap on the container before I put the lid on as well.