Possible deficiency at 5-6 weeks flowering

[cocogrower123]

I have 4 plants of the same strain, a 8 week finishing indica. 2 of the biggest and imo most developed plants started to show these symptoms of bud leaves getting brownish spots after week 5 in flowering. Currently nearing end of week 6.

2 of the abit smaller and maybe abit less developed plants dont show these symptoms at all.

Medium: coco 6 liter handfed 3-4 times a day to runoff
Light: Gavita 1700e pro at 100% ( 20 inches from top)
Nutrients: Canna A + B currently at 2.8ml per liter and Canna Zym at 0.5ml per liter netting a total of 1.5EC with my very soft tap water.

I was giving them 0.2EC of epsom salts every feeding in the nutrient water until I spotted the issue and stopped using it, because I thought it could be causing lockout issues - Not sure if my ca-mg ratios were fine..

The plants runoff seems give or take same what is going in, maybe even abit less on the affected plants so I'm thinking no salt buildup and instead a deficiency ? Its happening most on the top of the plant and the middle buds seem very healthy. Maybe K or P?

Any input welcome!

 

[cocogrower123]

was also thinking it could be the led light being too powerful but I'm also seeing this effect on the top of some colas that are more to the side and a lot lower than the ones in the pictures.

 

[cocogrower123]

@Aqua Man @Anthem maybe?