Information on denitrifying, ammonia, nitrogen cycle, and the importance of this marine live sand it your aquarium:
Marine fish drink the water in their environment constantly and excrete small amounts of very concentrated urine constantly. Combine this concentrated urine with fecal pellets, multiply that by several fish and throw in a good measure of uneaten, decomposing food into the equation, and we get ammonia.
Small amounts of ammonia is deadly to fish and corals.
In order for marine fish and corals to survive and thrive in our enclosed aquarium environment, we need to develop and cultivate a healthy population of beneficial bacteria that will neutralize the ammonia. Breaking down ammonia is necessary for the nitrogen cycle to begin.
Once allowed to multiply, these bacteria will populate the hard substrate in the tank, including the live rock, sand bed, tank walls and even the surfaces of powerheads and pumps. If it’s underwater, these bacteria will colonize it.
The first group of nitrifying bacteria — the aerobic, oxygen-loving Nitrosomonas — break down the ammonia produced by fish waste into nitrite (No2). Nitrite, while not as lethal as ammonia, is still poisonous to aquatic life. The second group of oxygen-loving bacteria, Nitrobacter, consume the nitrite and convert it to nitrate (No3). Nitrate is far less harmful to fish and is easily tolerated unless it reaches very high concentrations of 200 ppm or more