Heat stress? Rust? Need help identifying problem

[sunshineEtron]

We recently moved our sativa plants into a different room. Within a few days they have gone from being completely healthy to rapidly deteriorating. We know we have a heat problem, it is 90 plus degrees in the room but we are not sure if this is causing heat stress. Any advice would be great! Thanks for your time.

 

[JJ Bones]

It looks to be potentially a combination of phosphorous and potassium deficiency between photos. Give it a good flush, and remix the nute solution, obviously be sure pH is on point.

If your in the 90 degrees and you're not running adequate CO2 then they will stop growing. Similar to us (humans), we don't want to work in too hot of weather. I always think if I'm not comfortable in my grow room, better yet if it's not easy for me to fall asleep in there (due to heat, humidity, whatever), then my plants probably won't perform optimally which tells me I have things to fix.

 

[Magiccloset]

I dunno. This looks like calcium or magnesium deficiency. Are you using RO water ? Adding Calmag ? How often ?

 

[Magiccloset]

Also, are stems purple or red ?