What is particularly interesting for us about the Redfield Ratio is that it gives us a clue as to how to control waste build-up in our aquariums. Our aquariums are not a natural environment, however, the inhabitants will still follow the same rules as on a living reef. We can be assured that the Redfield Ratio will still impact the system. In the end, the chemistry doesn't change.
What does change is the unnatural amount of nutrient we add to our aquariums. As on the reef, the nutrients reach a state of breakdown of ammonias and phosphates. On the reef we find plenty of bacteria that will assimilate these wastes and remove them from the water column. These wastes are not actually gone, they have simply changed their state by being incorporated into another life form. Plankton! Bacterial, plant and animal. As we know, plankton is, also, a food source for many creatures. Clams and other molluscs filter it from the water, as do sponges, tunicates, various worms, etc. In an aquarium we rarely have enough of these filtering life forms to compensate for the wastes of our larger , non-filtering life forms, should we manage to produce enough waste product assimlating bacteria.
Going back a step to the bacterial plankton, we have learned that its production follows the Redfield Ratio, 16C : 16N : 1P. In a typical aquarium, the wasteproducts containing nitrogen (ammonias:NH3, nitrates:NO3, nitrites:NO2) and those containing phosphorus (phosphate: PO4) are more common than carbon. The aquarium becomes carbon limited and the levels of these waste products rises. Without sufficient carbon, they cannot be converted into (bacterial) plankton. Conversely, one may have sufficient carbon present from carbon dosing, but not enough nitrogen, which leads to a rise of phosphate,a common scenario in older tanks during changeover to a probiotic system. One can, also, have a phosphate limitation, which will lead to the nitrogenous waste level rising. Balance is the thing.
In an effort to maximise this cycle, we add a source of carbon to the aquarium water. First experiments were made with alcohol, sugars and acetic acid (vinegar), amongst other chemicals. This is based on a long used technology to treat waste water in water treatmant facilities. It is really nothing new, simply the application is new.
Suffice it to say, these methods work. Some a bit better than others, but, as each aquarium is a bit different, one cannot expect identical results. What is clear is that pushing the Redfield Ratio reaction reduces nutrient waste levels in closed aquarium systems. We don't know all the complex chemistry that lies behind this nutrient reduction, as this is not a simple path, rather a complex network of possible reactions that lead, via bacterial guilds, to this reduction.
Now, one of the first things one will notice, if they pour a capfull of vodka into a nutrient laden aquarium, is the aquarium water clouds overnight. Often accompanied by the death of many, if not all, of the higher life forms. Shock of shocks! Well, one does learn from this, as it doesn't have to happen this way.
What has happened is that enough carbon has been made available for a massive bacterial bloom in this closed system. In and of itself not bad, but, quickly reproducing bacteria take the oxygen out of the water so rapidly, that the higher life forms asphyxiate from lack of this life giving gas. This is why one starts slowly to convert a standing aquarium to a probiotic system.
As I mentioned above, it is a rare aquarium that has enough filterfeeding organisms to remove the produced bacterial plankton. This removal is mechanically done via a protien skimmer. But that is another subject.
What does change is the unnatural amount of nutrient we add to our aquariums. As on the reef, the nutrients reach a state of breakdown of ammonias and phosphates. On the reef we find plenty of bacteria that will assimilate these wastes and remove them from the water column. These wastes are not actually gone, they have simply changed their state by being incorporated into another life form. Plankton! Bacterial, plant and animal. As we know, plankton is, also, a food source for many creatures. Clams and other molluscs filter it from the water, as do sponges, tunicates, various worms, etc. In an aquarium we rarely have enough of these filtering life forms to compensate for the wastes of our larger , non-filtering life forms, should we manage to produce enough waste product assimlating bacteria.
Going back a step to the bacterial plankton, we have learned that its production follows the Redfield Ratio, 16C : 16N : 1P. In a typical aquarium, the wasteproducts containing nitrogen (ammonias:NH3, nitrates:NO3, nitrites:NO2) and those containing phosphorus (phosphate: PO4) are more common than carbon. The aquarium becomes carbon limited and the levels of these waste products rises. Without sufficient carbon, they cannot be converted into (bacterial) plankton. Conversely, one may have sufficient carbon present from carbon dosing, but not enough nitrogen, which leads to a rise of phosphate,a common scenario in older tanks during changeover to a probiotic system. One can, also, have a phosphate limitation, which will lead to the nitrogenous waste level rising. Balance is the thing.
In an effort to maximise this cycle, we add a source of carbon to the aquarium water. First experiments were made with alcohol, sugars and acetic acid (vinegar), amongst other chemicals. This is based on a long used technology to treat waste water in water treatmant facilities. It is really nothing new, simply the application is new.
Suffice it to say, these methods work. Some a bit better than others, but, as each aquarium is a bit different, one cannot expect identical results. What is clear is that pushing the Redfield Ratio reaction reduces nutrient waste levels in closed aquarium systems. We don't know all the complex chemistry that lies behind this nutrient reduction, as this is not a simple path, rather a complex network of possible reactions that lead, via bacterial guilds, to this reduction.
Now, one of the first things one will notice, if they pour a capfull of vodka into a nutrient laden aquarium, is the aquarium water clouds overnight. Often accompanied by the death of many, if not all, of the higher life forms. Shock of shocks! Well, one does learn from this, as it doesn't have to happen this way.
What has happened is that enough carbon has been made available for a massive bacterial bloom in this closed system. In and of itself not bad, but, quickly reproducing bacteria take the oxygen out of the water so rapidly, that the higher life forms asphyxiate from lack of this life giving gas. This is why one starts slowly to convert a standing aquarium to a probiotic system.
As I mentioned above, it is a rare aquarium that has enough filterfeeding organisms to remove the produced bacterial plankton. This removal is mechanically done via a protien skimmer. But that is another subject.
