They are crawling on the snakes and tubs. I soaked them in water with dawn to get hem off of them. Sprayed the tubs and racks with reptile spray. Done this 3 times in a week and checked the morning and they have them again. People I seen swear by front line. I guess everyone has different methods that work. I was just confused if you only treat the snake with front line it doesn't seem like it does anything with the mites that may be on the rack itself.