I'm new to frogs, but I found plans for a home-made humidifier that seems to be working well, as it's holding my viv at about 75-90% humidity. All it took was a water dish, an air stone, some air hose, an air pump, and a timer to make the air pump turn on and off. I have mine set to run for 15 min every hour, and it's working like a dream. I have trouble keeping my humidity up and this has really helped.