Backyard Aquaponics
A place to discuss aquaponics

Most of the larger tanks around here don't use rocks in the bottom because they just provide spots for solids to get trapped. For aquariums and smaller tanks it may not matter as much because they are pretty easy to clean. I haven't checked but I suspect an aquarium with an under-gravel filter probably grows plants pretty well as long as you're feeding good quality food to the fish. If I had an aquarium it would be easy to find out, just do a test for nitrates.