Help - What Deficiency?

[Voss]

So I'm having some problems with this lady, if anyone can help me identify the problem/deficiency..

it started showing those signs approx in second week of flower, she is now in 4th week flower. Never used anything else than the Biobizz Grow & now in flowering Biobizz Bloom and ofc pH down. We do however have pretty hard water (don't have the TDS meter, so
no known ppm). Leaf stems do have reddish/purple color, but only on the upper side.

Strain: Critical mass
Substrate: Biobizz LightMix
pH: 6 - 6,5 (runoff approx 7)
Fertilizing: in veg - Biobizz grow 0,7ml/L ; in flower - Biobizz bloom 1,5ml/L
Light: 300W LED

 

[Toaster79]

I assume those leaves are from the bottom of the canopy where light doesn't hit them? I'd say water less and more often and don't let your medium get to dry but also don't keep it too moist for too long. Get yourself some mycos and give them some molasses here and there. You also got some burned tips amd some of the tips are clawing which indicates you're overfeeding and youve got too much nitrogen in there. I'd give them some areated compost tea right now for at least two watering cycles and let the microorganisms break down the excess of nutrients.

 

[Voss]

Yes, forgot to mention - those are all from the bottom of the plant or somewhere between bottom and middle. I'm still new and learning, so first mistakes :D I was watering 1L so far (30L pots), there is always around 10-15% runoff. But do water after plant droops a bit. I did a flush two days ago also. Also is it a normal process that in 4th week of flower the smell is not so intense anymore (if you snap a leaf off or touch it, it smells a lot, but other than that it's not that intense) as it was in late veg? Should the buds start smelling by now?
Thank you for helping!