Grey spots

I’ve been growing WW in soil for about a month now and wasn’t happy with how it’s going. I hated guessing at what nutrients it was taking in so I decided to put it in coco. Long story short the grey spots have gotten worse. Any idea what’s going wrong? It’s in a indoor tent, around 70 degrees and 50% RH, under a 250 watt led and ive been feeding it a 1/3 of the recommended dosage of the GH trio with calimag

Also the leaves are curling a bit up. Is it imperative to get run off in coco? It’s a big pot for the plant to start so I feared over watering it

Any ideas??