i use the sunleave grow rocks,their fired shale,they only need to be rinsed once,and are ph neutral,i put it in 6in nets,i cut a 6in hole in the 3gal bucket lid,and the roots just hang down from the bottom of the nets,(unrestricted for growth) and for an oxygen kicker i put a small airstone at the bottom of each bucket in the water that remains in the bucket,as well as two large airstones in the res, they get a bubble flood 4 times a cycle,they love it! the rocks are very easy to reuse,a quick rinse in the net pot and their ready to go again,i use less rock,less cleaning,less weight,kind of a dwc/ebb and gro/bubble bucket (excuse the quality of pics,but it will give ya the idea)
and folgers coffee lids fit over the pots perfect lol