i was using 6" rockwool and top feeding. roots exploded out the bottom ands i was having this same issue so i put them in some soil. they started to get better then they took a turn for the worse. what do u mean trace element? temps r perfect. wet roots maybe.
Some advice.. You need to invest in bigger pot/s, 5 or 7 gal minimum if you wanna grow proper bud in soil. Then transplant that biatch of a rockwool cube INTO the soil, not on TOP. (making sure to take the plastic off the sides of the rockwool) That is where you are having probs with droopy leaves ie watering too much. You can't properly judge watering requirements if you have rockwool on top and then soil at the bottom.
If you are feeding every how many cups a day you said you were feeding, and their roots are now in soil, you are drowning them hence droopy leaves.
While your soil is still wet, the roots in the rockwool dry out... then keeping the rockwool moist is making your soil too wet....See where im going with this?
With a 1k mh that plant wants to sent it's roots through the foundation of your house lol trust me..So they want more space in soil. Hydro is a diff story.
I would also suggest feeding much less than you are currently feeding, if you're planning on carrying on using soil, you WILL fry them this way.
If you already have a nice setup with proper lighting and what not, why make things so difficult for yourself?
Good luck,
Trich