Bronze spots building up around leaf edges / medium drying slower / weaker than peers

Hi grandmasters - curious to know what’s going on with these 4-week flowering birkinz:

- seeing brown spots building up around the edges of leafs
- medium drying slower than healthy peers
- buds noticeably developing slower

I run Floraflex hydro salts with coco under 650W LED at full blast (12-24 inches away from canopy)
Temp
RH = 60

Pics attached. Any insight is welcome!!

Potassium deficiency off my cough.