To me the yellowing of leaves is possibly down lack of nitrogen in ferts......check the nutrients your using for nitrogen content....it should be printed on the bottle and the nitrogen should be the larger percentage for your stage of growth!!!! Bear that in mind!!
firstly i would stop spraying the leaves with food/water twice each day,it stops the leaves breathing if constantly wettwice a day is to much...
Stop it now and you may see the leaves stop sagging in 2/3 days.

If that fails i would change your watering schedule..especialy if you plant leaves started sagging a few days after watering..
Instead of watering and feeding once a week i would divide the water you give them into 2 days. The first day just water them......then give it 3-4 days and water again with nutrients ,

make sure your using a high content nitrogen food as this is what usaully cause leaves to yellow

Secondly i (had this with mine) droopy leaves may be caused by
over-watering....Take note if the leaves perk up when the soil is dry...if so..
then divide the water twice a week rather than drowning it one day with water then letting it go dry for 2-3 days....Remember little but often !!!!
If the soil is dry 10mm or 1/4 inch under the top layer of soil...its time to give a little water

Stop foilage feeding/watering especialy 2x a day ,plants can take water in through there leaves and with doing it as much as your doing will block the pores on the leaves which will suffocate the plant + you could cause mold on the plant if its always damp.stop spraying it

Good luck and rember a good plant food is always worth it not sure what yours is like,,,,,get a high nitrogen food and your away good luck and post back if you need to...keep us informed