calcium deficiency?

hey guyZ
plant are in coco, 50 days of 12/12, 6different strains from barney
quantum boards, temp 23 celcium day and night, humidity 43-48%.
feed em for last 30 days without changes :
EC 1.6-1.8 , PH 6.1-6.3
TAP WATER 0.6EC
PK 13/14 0.4EC
CANNA COCO A 0.3EC
CANNA COCO B 0.3EC
blackstrap molasses every 3-4 feeding

many leaves on 90% of plants getting yellow color ,and showed signs of burning.
can this be calmag deficiency? i stopped give them calmag after turned on 12/12. coco was buffered by me.

With your tap being that high EC, you very likely don't need calmag. Without seeing pics, I'd guess you're probably getting potassium and magnesium lockout from an excess of calcium. You could also be getting salt buildup which would look similar if you don't fertigate often enough.

What's your feeding schedule?
Do you feed to run off?
Do you ever use plain water?

Answer those questions ^ and provide a full pic and relevant close up pics.