What are these little brown spots

[BUDZY_MGROWN]

Im growing with livingsoil and have followed the instructions on the pack to the T but there was no mention of ph on there so i just ph between 6.5-6.8 from the start which seemed fine now im hitting 5th week of flower and the other day i noticed this brown spots on leaves and a touch of yellowing especially the main kola image shown any ideas on what this could be or if it's anything to worry about at all any help appreciated cheers

 

[Dosifry]

Looks like calcium deficiency especially w that leaf curl and it’s at the top of the plant.

 

[Dosifry]

Your ph is right on the money for calcium absorption. Just throwing this out there. Good luck

 

[RealizedReal000]

I would check the mediums ph.