If you're cloning in the aeroflo2, I've had the best success with the water level touching the bottoms of the net pots. Once you see several roots coming out of each cup, you can drop the level down. I like to keep about 1/2" - 3/4" of water in the tube to act as a buffer if there is a disruption in spraying(power outage...). Your pump should either run 24/7 or on a timer, 1 min on/ 5 min off is generally regarded as ideal. Once you go to flowering, you will not be able to leave the pump off for 12 hours, you will need to mist between.