Great thread.
Can I ask a few questions:
1. Are bioballs better than rings or will any filter material, including sponge do?
2. Is there a necessity for some space in the Denitrator, ie not to fill up with material to the brim? What's the reason?
3. Heterotrophic bacteria - how did they get into the Denitrator? Besides heterotrophic bacteria, will there be other forms of bacteria present that are harmful to fishes?
4. All anaerobic bacteria in the Denitrator will die immediately upon exposure to oxygen - is this true? Can some survive and find it's way back into the tank?
5. Is it a good idea to feed the denitrator with aerobic bb?
6. Is it a good idea to fix a UV to the Denitrator's output to kill any bacteria exiting from the Denitrator, as an alternative, say if one wants to be certain none gets back to the tank?
7. Besides bacteria, what else can be found in the Denitrator's output?
8. Why is it important for the control valve to be located at the Denitrator's input?
9. What is known to kill anaerobic bacteria?n ie besides exposure to oxygen.