they live in your soil or reservoir..... I hear if you go in while lights are off an a green light is on u van see the larva pop out of the soil. in my lp aero I USE CONCENTRATED H2O2 and those yellow stickey pads in the air.
if you have your environment stable best answer is that you pay very close attention water as needed. if I remember right my friend used coco and I think he watered daily.