Not sure what Deficiency this is?

Not sure if this is calmag deficiency.
It’s a GG4 in week 6 of flower.
Giving it fox farm trio and 5ml per gal of cal mag. Watering with RO water. PH is around 6.3
Also there are 2 other strains in tent and they are fine.

Me and my partner are dealing with almost the same thing our plants were cranking then spots on our leaves and wam within a week loss of leaves and dieing bottom branches out of nowhere anyone delt with thisbefore

Sometimes called “yellow leaf spot” or “leaf septoria,” this condition is caused by a fungus (or sometimes a bacteria) that attacks cannabis plants and usually appears in warm, wet weather. Cheers