1st time DWC Plz help keep me on track

Hey guys at RIU, first time poster long timer lurker. I just got into growing and i'm trying to make sure i don't do a horrible job at making some fire bud.

Started from seedling and these babies are 2 1/2 weeks old. they just started growing really fast as a lot of the roots are in the water and when the leaves started growing i started seeing this.

PPM-250
water Temp-68
ph 5.8
humidity-65%

Are they just getting more hungry now and its time to up my nutes or is it something else? I don't know what timeline i should be following starting from seedling

Any help is greatly appreciated!!

Can you get pics without the blurple on? Really hard to tell.

updated with more pics

Planted like that there is no airflow and the plant can't transpire. They transpire from the bottom of the leaf and also create their own micro climate around the leaf without good airflow well you get it....