Disease? Pathogen? Help!!

[Smoke2much4good]

So the plants were looking pretty good until just recently the new growth has started to come out looking funny and burnt and kinda of twisted a little and basically looking like its going to die off not sure why in coco with a ph of 5.8 everytime, i suspect fungal issue of some sort maybe aome kind of disease idk i know its not the ph any feedback would be very much appreciated thanks!

 

[Creeperpark]

It looks like a water calcium issue to me. I could be wrong, but it looks like you could use some cal mag in the fourth photo. If you are using tap you may want to change to RO and supplement it with cal-mag. If you are using RO then you need to add a little more to the water. Also the leaf tissue looks light burned from lacking calcium or bones so to speak in the leaf. If it was a Pathogen in the roots, the tops would be mushy which its not.

 

[Complete Noob]

In coco I shoot for a ph of 6.2. I personally would be scared to water with 5.8 water. I know that’s what you read online, but from personal experience 5.8 is probably the absolute minimum that your ph can be before you start creating issues. I don’t mind using water as high as 6.5. I actually started seeing issues around 6.6-6.7 at one point I wanted to see how high I could go. My kids looked similar to your pics here, so I resumed feeding between 6.2-6.5 and everything returned to normal after a few days