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Unread 12/18/2017, 08:14 AM   #20
Belgian Anthias
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Join Date: Oct 2009
Location: Belgium
Posts: 608
I have no doubt that carbon dosing works to remove nitrate from the water column. It is also a fact that dosing carbon increases the bio-load in the system and it becomes part of the food chain. What happens when dosing is stopped for some reason?

Articles about carbon dosing do not take in account the daily overproduction of nitrate. An aquarium system can have a concentration of 10ppm nitrate and be perfectly in balance at this level, production equals consumption. What happens when in such systems carbon is dosed to lower the level?
An aquarium system that is perfectly in balance at a nitrate concentration of 2ppm and daily doses of in total 2ml/100l vodka40%. What will happen when the dosing is interrupted or stopped? Would it be possible that the same system finds its natural balance at a nitrate level of 10ppm without dosing?

Skimmers remove max +-25% of DOC and max 35% of TOC available in the water column and are very selective in removing live bacteria which is an issue worth to be researched. Most of TOC is not available for skimming as it is bentic. http://www.baharini.eu/baharini/doku...iwitafschuimer

The theory behind carbon dosing and the removal of the biomass by a skimmer stands. But only for a small amount and the removal is certainly insufficient to prevent build up of the bio-load.

Before the nitrate will be used the immediate available ammonia NH4 is taken up. The assimilation of ammonia NH4 by dosing carbohydrate consumes alk by producing CO2 using inorganic carbon from alk; Once nitrate is taken up it is transformed internally into NH3 , one must take in account the respiration. When the produced protein is consumed most is released in the water column as NH3 and is ionized to NH4. When not consumed all is released and used during decay. Ebling en Co take all this in account also the alk shift in seawater.
All this results in the fact that +- 3.57 gram alk is consumed for each gram N

Table 4. Stoichiometry for heterotrophic bacteria metabolism of 1.0 g NH4+–N with carbohydrate as supplemental carbon (EblingEnCo2006>http://www.baharini.eu/baharini/lib/...0216x-main.pdf)

Heterotrofe ammonium reductie http://www.baharini.eu/baharini/doku...onium_reductie

The work of Ebling en Co does also covers photoautotropic and autotropic ammonia reduction in ZMAS.

In zero emission marine aquaculture systems (ZMAS) for cultivating shrimp carbon dosing is common practice and is used as part of the food chain. Measures must be taken to compensate for the alk consumption due to carbon dosing. In these systems the production of nitrate ( nitrification) is prevented by the high C:N ratio. After a period of time the cultivated biomass is harvested.



Last edited by Belgian Anthias; 12/18/2017 at 09:02 AM.
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