Welcome to the forum Howe be sure to read the dart frog vivarium articles Frog Forum - Building Dart Frog Terrariums / Tropical Terrarium Construction The easiest way to keep the 80-100% humidity would be to have a glass aquarium top on your tank to trap in the humidity. A hand sprayer is usually enough depending on the size of tank but since you wish to get away for a couple days, i would suggest getting a fogger or a misting system designed for vivariums. Live plants such as pothos, wandering jew and some ferns make great additions to the dart frog tank and will also help increase the humidity within your tank.