veg plants new growth turning brown

Hi,

I'm in the 3rd week of veg and all the new growth is starting to die off or turning brownish. I'm doing dwc, 900ppm ph 5.8, strain is an Afghan crossed. It's starting from the bottom and moving it's way up. the fan leaves are even curling up really bad. Here's some pictures. Thanks in advance!

what nutrients are you using?

Way too strong PPM for week 3 of veg and your plants being so small (from what it looks like). Dilute to about 400 PPM for early, you wanna hit about 900-1200 PPM in the middle of flowering. Are your roots hitting the water yet, and if not are you using a drip emitter until they do?