@Redzo 
welcome to AFN
That looks like a Phosphorous problem but too much or too little or is it a lock-out? Can you give us some more information.
Please fill in this form: (copy and paste part is below, this first one tell what specifically to include)
-Problem: (brief description)
-Medium/grow method: soil; soilless-- coco, or peat based like Promix, etc. (please provide the actual product name); DWC, NFT, etc.
-Feed and supplements used: include brand, dosage/strength, frequency of feeding and watering (alone); method-- by hand, drippers, rercirc' or drain-to-waste,... N-P-K #'s too if you can!
-Water source: RO/DI; tap- dechlorinated-?..... EC or TDS reading; pH (don't bother with this on RO/DI, do bother with TDS/EC though to confirm it's working well enough)
-Strain and age
-Climate: night and day ambient T and RH%; res' temperatures; any extremes in T/RH% exposure
- Light used: HID, LED, COB, combo of,... wattage; light cycle hours (20/4, 18/6 , etc.); distance to tops....
-Additional info: PH in the root zone. How long have the plants been affected?...How fast did symptoms appear?... Anything else you think might be relevant..
--Pictures including WHOLE PLANT PICS, and troubled leaves.. use normal light or flash as other light sources ruin color rendering, critical for diagnostics! Turn off the grow lights.
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(copy and paste)-->
Problem:
Medium/grow method:
Feed: and supplements used:
water source:
PH in the root zone:
Strain/age:
light used:
Climate:
Additional info:
