Help!! - big bang auto greenhouse seed - leaf discolouration

Hi all I have this morning found some leaves on my Big Bang Auto and hope someone can enlighten me as to the problem.

Here is my set up:

Coco - with Canna A+B, Rhizotonic, Cannazyme.

The air temperature is between 22 - 28'c
The pH is 6.4


RH - 45%

Any help will be much appreciated - as there are other plants which are fed from the same reservoir and they seem okay!

If you are growing in coco and feeding at pH 6.4 then you probably have a lockout there. pH 5.8 - 6.2 is the ideal range for coco growing.

Have you checked the underside of the leaves for spider mites?

Yeah no mites from my checking but I did find some of the leaves below precipitating. Almost sweating - Think this could be it? Or perhaps from foliar feeding?

Thanks

I think you have a calcium def.As you can see from this charthttps://www.rollitup.org/attachments/marijuana-plant-problems/2925767-can-you-look-my-plant-phrangechart_zpsddd4a5c5.gif that calcium will be locked out at 6.4 ph.Coco is classed as hydro btw.
Get your ph down.I usually aim for 5-5.5 as i find that ph always goes up in coco after watering

I agree Calcium deficiency.