It's possible you have root rot. Even though res temps are on the low side (where they should be), there are still some pathogens that are able to replicate, causing damage at lower temps. If this is the case, look into a Silica product like Pro Silicate.

Let me know if this helps. Keep us posted!
purpleskunk777 Reviewed by purpleskunk777 on . A little Help for a LittleGreenman! (any help appreciated) I am a fairly experienced grower but this is my first grow with auto's using the ebb/flow type setup. The top set (newest growth) of leaves is drooping and I can NOT figure out why. I did a res change yesterday and got no changes. It really looks like moisture stress of some sort but I really can't figure out why, I've tried watering less (once a day), I've tried watering more (once every two hours), I've tried not watering, nothing, no changes.... I'll post some pics so you guys can see. Rating: 5