alrite smokers.my plants r still growin up and out,butthe bottom leaves r dying.i was told it was either salt build up or nute burn.so 2 days ago i cleaned the all system with fresh water and put fresh nutes in fresh water.i also added some liquid oxygen and superthrive. my ph is now staying at 6 and humidity is 60-75%,temp is 23-27c and ive lowered my cf to 16. what could b wrong with em??? plz help b4 they die