Was haben meine Pflanzen?

Sounds like your girls are just hungry. If you only started feeding in week 7, that discoloration is probably from a lack of nutrients earlier on, not too much light. If they're handling it well, I’d keep feeding the Hesi Bloom at 5ml/L every few days. Don’t cut the light unless you see signs of stress like bleaching or tacoing leaves. Also, make sure your pH is in check (around 6.0–6.5), or the plants can’t absorb the nutes properly. You got this—autos move fast, but they’re forgiving if you catch things early.