First nutrients; they do change to non bio available forms as bacteria exhaust them and in turn are consumed by other bacteria and so on until all of the useable energy is gone. In an overly simpified understanding :the C(organic carbon) and N will ultimately go (there are many forms along the way ) to acetate or further to methane via anaerobic digestion /fermentation ; the N once freed from the H in ammonia or the O in nitrite and nitrate will go to N2 .
The C will be replaced by athmospheric CO2 via photosynthesis. The N is reintroduced into the food chain from the athmosphere by diazotrophs including cyanobacteria which break the N2 bond with a unique enzyme nitrogenase.
Nutrients breakdown and are reintroduced constantly in a living reef; the quantity of nutrients in an aquarium is not a fixed amount but a moving target. On our tanks skimming , granulated activated carbon, etc. help offset the continuous input from foods via the export of organics. Given time the food would ultimately disappear as a source of nutrients leaving precipitated salts/ sand. . The trick is getting enough of the right kind of microbial activity ,sometimes aided by chemical an mechanical filtration to support the extraordinary density of life in our tanks compared to ocean densities and to insure a rapid enough export via the biofilter , chemical adsorbtion , mechanical means,etc.to maintain conditions in the water beneficial to the corals , fish, etc being kept in it.
The different bacteria performing different steps need variable amounts of OCNP and oxygen among other things.
It is quite possible in my opinion that Paul's success with the rugf has much to do with the amount of flow( not too much and not too little) to enable a vibrant bacteria culture via the delivery of CNP to them for nitrification and denitrification and possibly some organics break down too.
The C will be replaced by athmospheric CO2 via photosynthesis. The N is reintroduced into the food chain from the athmosphere by diazotrophs including cyanobacteria which break the N2 bond with a unique enzyme nitrogenase.
Nutrients breakdown and are reintroduced constantly in a living reef; the quantity of nutrients in an aquarium is not a fixed amount but a moving target. On our tanks skimming , granulated activated carbon, etc. help offset the continuous input from foods via the export of organics. Given time the food would ultimately disappear as a source of nutrients leaving precipitated salts/ sand. . The trick is getting enough of the right kind of microbial activity ,sometimes aided by chemical an mechanical filtration to support the extraordinary density of life in our tanks compared to ocean densities and to insure a rapid enough export via the biofilter , chemical adsorbtion , mechanical means,etc.to maintain conditions in the water beneficial to the corals , fish, etc being kept in it.
The different bacteria performing different steps need variable amounts of OCNP and oxygen among other things.
It is quite possible in my opinion that Paul's success with the rugf has much to do with the amount of flow( not too much and not too little) to enable a vibrant bacteria culture via the delivery of CNP to them for nitrification and denitrification and possibly some organics break down too.
. So you see, my statement it true 
, in our town I don't know of a single bare bottom or SSB tank. Not saying they don't exist, just saying that if they do, I don't know about them.
If you're trying to say that I don't back up what I'm saying with documented research, I'm really confused. I posted two links in the post you quoted.
