Is this Fusarium? Pest? Nutrient?

[Bstylee]

Hey guys,
I was hoping you could help me identify what is going wrong with a couple plants. The strangest thing about all of this is that it appears to be affecting only 2 strains (out of about 20 that we have) and it is affecting both flowering plants as well as veg plants which never recieve the same nutes or water.
All affected plants are in hydro (grodan in pots) and we use General Hydro nutes. The affected strains are afgooey and banana kush. The rooms are hot (80-88) but they have been this way for a while and this problem literally popped up in the last 3 days and is progressing faster than any destruction I have seen (besides just straight not watering).
I have been leaching the affected plants with RO pH'd at 6.0 (and it has been returning 6.0 with small gain in ppm) and it doesn't seem to be helping.
also I have checked the root systems of the plants in veg and they seem white and healthy

I just dont know what to do and don't want to lose these strains.

 

[codeCANNABIS]

i was reading this article on plants that have been over fed and my opinion is that your plant has been over fed usally the harm has been done im not sure if u can do anything but research and try and find a solution .... if im wrong some one correct me

 

[hbenz]

i am having the same problem not as full on as this though but definately got the same thing i am unsure of what is going on too i have flushed my plants out and waiting to see how it goes in the next few days will let you know how i get on cheers