HydroRon I dig your site. I built a 9 bottle (2 liter) pvc system. It works killer. Thanks for the plans. Heres the question. Since the cups are circular and the cubes are of course square the rockwool doesn't fill the lower portion of the cup. Should there be air in the bottom of the cups or should the rockwool fill the cup? Also how high should the
nutrient rise in the cups?
Thanks stork