The word "nutrient" and "nutrition" are commonly confused when talking about reefs. "Nutrition" is just like food; it feeds the fish and the corals and the microbes. Nutrition include fish waste, coral slime, leftover food particles, algae (yum sushi), vitamins, and amino acids. This nutrition can be in the form of pieces or particles that you can see, or very very small particles that you cannot see call dissolved organic carbon ("DOC") . All this nutrition feeds some animal or microbe somewhere in your system, and it is the carbon in this nutrition that is being sought.
"Nutrients" however are different; they are Nitrate, Nitrite, Inorganic (Ortho) Phosphate, Ammonia, and Ammonium, i.e., the things your test kits test for. There is no carbon in these; just nitrogen, phosphorus, oxygen and hydrogen. Nutrients are what remain after the food chain does it's work, all the way down to the last bacteria. This is also called "re-mineralization", because all the organic particles have had the carbon removed such that only the "minerals" (nitrogen etc) remain.
"Nutrients" however are different; they are Nitrate, Nitrite, Inorganic (Ortho) Phosphate, Ammonia, and Ammonium, i.e., the things your test kits test for. There is no carbon in these; just nitrogen, phosphorus, oxygen and hydrogen. Nutrients are what remain after the food chain does it's work, all the way down to the last bacteria. This is also called "re-mineralization", because all the organic particles have had the carbon removed such that only the "minerals" (nitrogen etc) remain.
