not sure about the yellow (although the simple answer in the veg states is always a lack of either Magnesium or Nitrogren).. But drooping is usually a result of either over watering or under watering..
MACHINE Reviewed by MACHINE on . Plants Drooping, yellowing also Plants are drooping at around 11pm every night. In the morning they look better, then they droop again. What is your experience level? (first timer, novice, experienced...) Novice What type of hydro set-up are you running? Top feed, hydroton Your Equipment: A) Type and wattage of lights. (MH, HPS, CFL's, tube fluorescents, LED's) 1000w HPS B) Distance from tops? 20" C) Reflector type? (cool tube set-up, bat wing, enclosed reflector, bare bulb...)Enclosed w/ glass Rating: 5