Limiting or promoting growth? Why do I prefer promoting growth?
In theory and practice, in a closed system, nitrate is produced in relation to the C/N ratio of the feed. The nitrogen content of food depends on the protein content of the food. The higher the protein content the more nitrate must be produced to maintain the carrying capacity of the system.
The basics are very simple.
A fish and other target organisms ( the consumers) eat the food but use only about 15% of it. With the exception of carbon (because from the organic carbon present in the food a lot is used for producing energy and is released as CO2) +- 85% is released, the nitrogen mainly in the form of toxic ammonia. The carrying capacity for supporting the bio-load is about removing most ammonia as fast as possible.
The carrying capacity is supported by 3 pillars. 1 heterotrophic growth ( reducers, bacteria needing organics), 2 autotropic growth (nitrifiers, bacteria and archaea) and 3 photo-autotrophic growth ( the producers, cyano, grasses, algae and all phyto)
Most of nitrogen in the food is released as ammonia and a lot of the organic carbon in the food is exported. Depending on the C/N ratio of the food pillar 1, the fasted growers, reducing the feces ( containing very little nitrogen) will use ammonia fast to grow ( logarithmic growth) A lot of the organic carbon is already exported by the target organisms, by the consumers, and pillar 1 will use up and export the rest. This means not all ammonia available can be used up by pillar 1, leaving produced usable inorganic nutrients, elements of the feces, behind.
Being the final part of the mineralization process pillar 2 plays a very important role and tries to use up ammonia left over after the feces have been broken down. Pillar 2 does not need much nutrients for transforming toxic ammonia into safely stored and usable nitrogen, nitrate. But as they are slow growers, because they run there own private energy production factory, some ammonia will be left for pillar 3;
No problem at all. If everything what was once in the food has been broken down into usable elements for growth, pilar2 and 3 will remove all ammonia left over and pillar 3 will use up all available nitrate , clearing the water off all nutrients. ( al lot , about 16%, of produced nitrate normally is exported by natural denitrification.) Depending on the composition of the feed all nutrients should be used up wile maintaining the carrying capacity by balanced growth.
Nutrient management starts with what is going in. The lower the C/N ratio of the feed ( high protein content) the more autotrophic ( pillar 2 and 3) the carry capacity must become to be able to support the bio-load, the more nitrate there must be produced. But as shown, this should not be a problem.
The problem is , what happens if the balance is NOT maintained.?
What happens if a good skimmer removes 35% of the organic carbon and other essentials once part of the feed but not ammonia? The system must become more autotrophic but pilar 3 may not be able to remove all nitrogen and phosphate because of growth limitations
What happens if a mechanical filter removes part of the organic waste but not ammonia?
What happens using the combination skimmer and mechanical filters?
In fact it is very simple:
The C/N ratio of feed ( mainly the protein content) controls the way in which the load-bearing capacity is supported, the division between 1 or 2 and 3 but only if organic waste once part of the food is not exported .
If organic waste once part of the food is exported but not ammonia the system must produce more nitrate to be able to maintain the carrying capacity needed, to be able to remove all produced ammonia.
If an unknown part of organic waste once part of the feed is exported but not ammonia it will be impossible to mange the nutrient balance by managing growth and by using balanced food.
What goes in can be be exported. This can be done by harvesting growth. by harvesting 3.
My conclusion: Most reefers create an unbalance and then one does try to correct this by battling the symptoms instead of threatening the cause.
Is it about battling the symptoms? Is it about balancing or preventing? or is it about eliminating the cause ?
Battling the symptoms based only on Nitrate and Phosphate overproduction is very simple using growth, using AAM in a refuge, active aquarium management. AAM can also be used for balancing the nutrients, all nutrients, also for curing or and preventing. AAM is about target feeding in a refuge maintaining the growth and growth rates needed for clearing the water. Growth is then harvested in function of the growth rate needed
