need a little help....dwc system

i was wondering about the dwc cause i just made one... right now i use hortawool as my medium. and i wanna get into these kinda systems. so i made one and well see how it goes. I just dont know too much about them. If the seeds havent rooted crazy yet how deep do u put the net pot in the water? i read 1/2 in. then when the roots start comin about an inch under the pot..also do a put the rock wool that i have seeds or clone in all the way to the bottom any help would be awesome thx.....heres a pic let me know i have the rockwool barely underneathe the rocks...i also have a 400w mh on top about 8 inch away...and the one in the back is my hortawool momma soon to be.....

rockwool in a dwc sucks for sprouting seeds. I plant them in soil and when they get 4-6 inches tall i put them in the dwc. makes things a hellava loot easier to me.

Did you say your 400w light is 8 inches away from your seedlings???? Way to close.
Move light up to around 20 in. You'll burn them babies.

yea i moved it...

how far should a 400watt be from the top of the canopy?