Why dose Organic Carbon?

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The main purpose to dose organic carbon is the reduction of excess nutrients in the reef aquaria. The two main nutrients reduced from organic carbon addition are nitrate and phosphate molecules (NO3 and PO4 respectfully). The reduction of phosphates, in turn, allows for enhanced calcification and growth of corals. Additionally, lower NO3 and PO4 have the added benefit of reduced nuisance algae, both bubble and hair. This observation has been reported numerous times by vodka users. The reduction in algae is the result of lower NO3 and PO4 within the water column and not a direct effect of ethanol addition. These potential benefits have lead some to add foreign organic carbon sources not usually found in the reef ecosystem to their tank. The organic compound most frequently used is ethanol (sold in stores as vodka).

The addition of vodka/ethanol is thought to increase bacterial biomass. For this, vodka addition would result in bacterial growth and reproduction. During this process nutrients in the water (including NO3 and PO4) are taken up for the formation of new macromolecules that are needed in cell synthesis and viability. Due to this rapid growth and reproduction, NO3 and PO4 can drop quickly from detectable levels by most test kits on the market. The increased biomass of the bacteria leads to a notable increase in skimmate production, removing more waste than without vodka addition. The increased skimmate is thought to remove the bacteria or bacterial biproducts that have assimilated the NO3 and PO4 within the water column leading to NO3 and PO4 depletion.

Many view organic carbon dosing as unnecessary as organic carbon isn�t thought to be limited in the reef aquarium environment since larger organic molecules are found within the water column at any given time. However, the amount of organic carbon that heterotrophic bacteria can utilize must be limited due to the reported benefits and observations on Reef Central from organic carbon dosing. This method is applicable for systems that have had the inability to effectively remove both NO3 and PO4 from their system. Stable systems that do not contain high levels of NO3 and PO4 may not benefit to any great extent by employing carbon source dosing.