Bioballs you see are referred to as packing material to help gas exchange as upward air flows against water trickling over large surface area. Idea would be to strip trace amount as it is generated. Not really necessary in managed tanks with light feeding but moster fish tanks and NPS tanks might benefit.

Likely energy intensive if it can be effective.My conclusion without trying it is that denitrators would be a better choice for a heavily fed NPS tank only because the nitrates can be easily measured as they decrease, and would be far less energy intensive.

Ammonia scrubbers are sometimes seen as process before primary effluent discharge on large farms with pigs, to take brunt of bioload of ponds or biofilters.