Actually that was extremely helpful

My only concern is the duration of time where the roots aren't long enough to reach the flood level, and are just in hydroton that is never flooded.

Incase you haven't noticed I like to be triple sure of things, apologies in advance but:

This means I do not put my rockwool slabs into the system until the roots are long enough to reach the solution... What do I do with the slabs while the roots are growing out of the bottom? Is it Okay in a glass tray?

If I feed them at 1/4 strength solution, But it doesn't touch the roots poking out of the rockwool, only half of my net pot, will the water Wick up through the bottom or something?

again apologies.. I'm annoying *myself* with the same questions over and over, so I could only imagine how you feel!

also how to I go about testing the PH of the rockwool itself? Collect the runoff I know, But how do I collect the runoff?