Hello james12man,
Your plants look like their suffering from a deficiency or toxicity. My first thought is the
nutrients your using. I don't know what it is, and their may be multiple reasons, but almost always when Epsom salt is part of the nutrients, they seem to have have problems. Do you have a link to the exact nutrients your using, as well as their mixing chart? Also algae won't actually hurt your plants, however besides being messy and slimy, in extreme cases it may use up oxygen the roots need if there is enough of it in the reservoir to lower the dissolved oxygen levels.
That being said I have some questions
1. What type of material is the grow plug, and is it wet (soaked). If it's to wet it could be causing stem rot.
2. How much water is at the bottom of each 5 gallon bucket?
3. Is the perlite soaked, or just moist.
4. When the plant droops, is the sun directly hitting the foliage, then the plant perks back up again when it's shaded?
5. What are you using for your water source?
6. What is the water temperature (both night and day)
7. What is the air temps (both night and day)?
8. Does the water in the reservoir look murky or cloudy?
9. Does the water in the reservoir smell bad and/or musty?
10. How often do you check your pH, and are you using pH drops to test it?
11. How often do you change your
nutrient solution?
12. Are you using a air
pump and air stone/s in the reservoir?