when does rockwool cube go into clay hydron pellets

4 inches tall,sprouting second set of leaves ,look healthy strong ,root out the bottom of 1.5x1.5 cube ph balanced under 2-2ft 55ook varilux grow lites.i have a 15 gallon bubbler set up with 5 -5 inch netted pots.when do i transplant under 2 red/blue 225 led ufo lites.how far down does the cube go.i'm guessing to the bottom to let the bubbles spray/mist the roots .just add clay hydron pellets for root support anbd moistures ,any info/input???

Get it in now. Put a layer of rocks on the bottom, then the cube, then surround the cube with rocks. The top of the cube should be at about the top edge of the netpot. You may want to read the link below on the bubbles, you have the right idea there.