real quick DWC question

At what level to or above the bottom of the net pots do I put the water level when i have small roots showing out of the rockwool cubes.

I have hydroton in my clay pots and until the roots hang out of the pots I keep my level about 1 cm above the bottom, then I let the level drop and keep the water below the pots after that.

just put them on some hydroton rocks w/ water level a bit lower so it doesnt touch for a few days