Please look , any advice is welcome.. rust spots and curling

Can anyone HELP me on whats going on .Using dwc in 5 gal buckets.GH nutes Flora, Micro,Bloom w/b52 and calmag.Water level is just touching net pots.
Growth seems good .Not yet 4 weeks old from seed.Getting brown rust looking spots and curling edges of of leaves...

here are more pictures

More pictures

tap water or ro? and whats ph?

looks like cal/mag maybe u r locking it out due to u adding it when dont need it?

what im seening on a few leaves is over nutrients . cut back strength for a bit start going full strength when they get a foot tall or soo i would bet a thousand dollars thare over fed with fertilizer prob better to run 1/4 , strenth nutrients, rem when they get bigger then you can start power feeding them,

thats defintly 100 % neutrant burn ,

dont nutrient burn start at the tips?

Thanks people I'll cut back on the nutes. Arron I'm using tap water but letting sit out. Also the guy at the hydro store sold me a bottle of chloramine remover. I check the ph twice daily and I keep it around 5.8 -6.0