Definition: Ammonium is the ionized form of ammonia, which is occurs when the water is acidic. It is not as toxic to fish as ammonia, which is why aquariums that have acidic water do not have as many problems with the intial phase of the nitrogen cycle.
Ammonium, the most important nitrogenous fertilizer for water plants, is essential for the breakdown of plant protein.
Also Known As: NH4
