[I think Nitrifing bacteria, nitrosoamans(sp) are responsible for breaking down ammonia into nitrite and then to nitrate. This occurs in aerobic sections of anything in contact to or under water and has a texture (not sure if they would grow on bare glass). Live rock, bioballs, the top layer of sand, biowheel, etc...
Anerobic (anoxic) areas are deprived of oxygen deep in a sand bed, or inside live rock, or in special denitrification filters with water dripping through them and a media to colonize. In these spaces are anerobic bacteria known as (sorry I forget). These consume the nitrate and turn it into free nitrogen, which is harmlessly off gased into the tank and into the atmosphere.
When this gas builds up due to going stagnent (lack of substate mixing) it will turn to a sulphate gas which is highly poisonous to livestock. I have unfortunatly whiped out 2 of my cichlid tanks due to this, to deep a gravel bed with nothing to stir it but me and a lack of husbandry.
Thats why you either need a very deep sand bed with lots of fauna to turn it over well, or a layer less then 2" with plenty of fish/inverts to stir it for you.
Keep in mind that they are talking about treating drinking water it looks like and treatment plants. They are using chemicles, and many other filters/process we do not/cannot.
An interesting side point I noticed this ...
"When you start converting ammonia (NH3) to nitrate (NO3) in the aeration tank many hydrogen ions will be released. When alkalinity drops below 50 mg/l your pH can drop dramatically."
That is basically what happens to fish that travel in bags, ammonia builds up and drops pH, the change back to a high pH holding tank is what will do a fish in for sure. Luckily ammonia is much less toxic at a lower pH. (I've seen salt water fish come out of bags with a pH of less then 6)
Sorry if thats not what you were looking for or way to much
Wasn't 100% sure what you were looking for.]
Edited By mwolek on 1093309027
