That is waayyy too hot for res temp. 64/65 f or 18C you probably do have root rot. Check roots if brown and slimy then that’s your issue, or at least part of it.
There is also a product called perfect ph. It essentially keeps your res ph at the value you set it and lasts a very long time. Just google it 
Here’s the link:
Seems like a cool thing but are there sizes below 35 gallon?
No not at the moment. But you could make/buy a bigger res then connect your tubs with hoses and a pump, then you will have a rdwc (recirculating deep water culture system
Here are some updated pictures, each day there is noticable vegetative growth so I think I may have dismissed the problem.
You have to figure if what your going through is mobile or immobile …
Elaborate please?
And also, these plants are halfway through week 3 and the only sign of malnutrition/infection was on the first set of leaves
So issues with plants can either be mobile or immobile meaning it might start at the bottom and move to throughout the olant or it can stay in one area of the plant. That will better help you diagnose if your plant is getting better or staying the same … I say that because I once had a plant have beautiful new growth at the top but the middle remained sickly… so figuring that out helped me get the problem resolved … just food for thought … I’m not saying you haven’t healed your plant just something to keep in mind when your diagnosing issues since so many have similarities it helps to diagnose the proper issue …
Thanks Chris for the insight, the whole plant seems happy including roots so hopefully I’m on track
Then you should be good to go
