I hace a tank that is 2wide, 2deep , and 3 feet tall and I have a waterfall AND an ultra-sonic fogger. The waterfall operates 24 hours a day, but the fogger absolutely can not. I have the fogger go on for 15 minutes every hour, otherwize the bottom of your tank will get very soggy. Also, you have to take care that the geckos cant get into the fogger resavoir because it will heat up dramatically and if they get in it, you have really expensive stew. I have a rigid piece of clear plastic screwed to the top of the resavoir with 1/4" spacers holding it away from the top so the fog can escape. This will also stop the spray from the fogger from getting out and soiling your tank.