It depends on what you are trying to accomplish. If you were having a problem with ammonia, then this system would probably help. But bioballs in a bucket would be the same problem as a wet dry as far as increasing nitrates. They do a great job of capturing detritus and provide a great place for nitrifying bacteria to colonize. By capturing the detritus and preventing detrivores from reducing it, you end up with more nitrates. If you increased your nitrate removal somewhere in the system you'd be okay.

I have heard of deep sand beds in a bucket to remove nitrates. The dsb provides an anaerobic area for denitrifying bacteria to colonize. And after a period of time if you suspect the dsb is causing problems, you can remove the bucket from the system, replace the sand and your back in business.