Originally Posted by cmor1701d
How can the presence of oxygen create anoxic ("Absence of oxygen") regions?
Anoxic does not mean "absence of oxygen", it means reduced. It is an area that gets very little O2
and the bacteria that live within these areas are not strict anaerobes nor strict aerobes. Facultative bacteria that live in anoxic zones will convert nitrates albeit a little slower but do not render their foods in the same manner as strictly anaerobic bacteria. The end result in anoxic area's being primarily nitrogen and CO2
So how do you keep nitrates at zero without anaerobic bacteria?
It's really no different than any other set up with anaerobic areas. Keeping the bio load acceptable and responsible feedings will greatly limit the production of NH3
which are the sources of NO3
in the first place. My nitrates may not be zero but they never get above 5 ppm
and quite honestly IME
the ever sought after zero nitrates are not necessary.
Is the protein skimmer alone enough?
Are you doing constant water changes?
I do employ aggressive protein skimming in all my tanks but admittedly I rarely do water changes. I might need to do something every few months that may require a 5% change in the water but that will have no impact on the nitrate levels in the tank.
I also employ a great number of natural cleaners that help in keeping detritus and uneaten foods at a minimum. Sea cukes, stars and various snail species. Not to mention the many copepods, amphipods and mysid shrimp.