I'm growing some Purple Kush and Banana Kush. I've cloned them from my Mother plant. They do great at first and grow like a weed - then at about 30" to 40" they start dying on me. There are no fungus or fungus gnats, room temp is 83F and 40% humidity, using HPS lights that are 3-5ft away. One plant that died, I checked the root system and it looked fine. I've been feeding them fox farms and they are in Happy frog soil. I moved them to LED from the HPS (thinking the heat is doing this?). Today I "washed" 3 of them by soaking the plant in water in the sink to try and cleanse the system?I'm stumped - any idea's?