[sorcerer]

I've got a friend whose been using the bio rocker for about 9 months now. Whether it will produce the nitrates like bio balls seems to depend on the configuration. The biorocker by itself is doing the same function as bio balls in a wet/dry. Kent sells a de-nitrification slab made of the same cell pore material as the bio rocker that is meant to be completely submerged in the sump. In essence the slab acts like a large chunk of live rock and cultivates bacteria to reduce the nitrates. The combination does seem to be working for my friend. He bought the deluxe setup that has sump, rocker, and slab all in one unit.

The rocker itself will only cycle ammonia and nitrite to nitrate, the slab is what they use to handle the nitrate, at least from what has been described to me.
HTH