Not sure why they drooping like that.Do you think the sandy soil could be to much on the roots? Also you could try mixing a lil dishwash detergent (1-2drops) in a spray bottle with 1-2 teaspoon of Hydrogen Peroxide and mist them one time a day.

But im not liking the soil mix, if you could i would get something that holds water well and but also has good drainage. Oh how often do you water?

I also use a lil peroxide in with feedings (watering)