I use hydrotron in the waterfarms. I have 4 modules, I use the 13 gal res and have it recirculationg. Once my seeds germ, I place them in the RR until they sprout approx. 1.5" out of the top of the RR. I then place them in the waterfarms and cover the RR with hydrotron. My guy informed me to set the drip timer to come on for 15 min and off for 45 min. I will up that to either every 15 min or continuous once they are strong and at least 6-8" tall. Hope that ws helpful.