MObay, some guy on here.. awhile back... maybe it was HD.. not sure.. but he trimmed the shit outta his roots in a HYDRO system.. similiar to yours...

he did it as an experiment... he took pics for all of us to see... the plant with the trimmed roots, did just as well as the plants adjacent to it (without trimmed roots) in the hydro system..it was quite remakable actually...

Although I would never ever do that..LOL

AND NOW YOU sorta KNOW