Leaves turning pale/crispy hours after watering/feeding!

Hey growmie, kinda tricky to say 100% without a diary, but from your description and pics I’d say you’re simply running a bit too soft on the feed for this stage. Volvic is super soft EC 0.2, so your plants basically get nothing from that in terms of calcium or magnesium. In coco or lighter mixes under LEDs that’s asking for trouble. They need calmag early to avoid stuff like pale new growth, yellowing after watering, rusty edges etc. Also if the leaves get worse right after watering, that's usually because the rootzone dries out too much, salts get concentrated, then weak feed goes in and they can’t buffer it properly = stress reaction. Would probably adjust like this: Add calmag first when mixing your water, bring EC up to 0.4-0.5 just with that. Then your normal base nutrients on top of that until EC 0.8-1.0 ,early flower is fine with that. pH 5.8-6.0 always for coco or hydro style grows. Always water until you get some runoff 10-20%, and check that runoff EC + pH every now and then, just to see what’s going on in the pot. I don’t think it’s bad yet, just gotta feed them a bit more steady now and avoid letting them dry out too much between waterings. Get a diary up next time if you can, it helps a lot . Good luck growmie 🤞🍀♥️