What You Need to Know
In this system, ammonia excreted by fish is oxidized by nitrifying bacteria (Nitrosomonas and Nitrobacter) to nitrite and then to nitrate, which plants absorb. The process is temperature, pH, and dissolved oxygen dependent, with optimal fish temperatures of 20–25 °C, pH 6.5–7.5, and DO >5 mg L⁻¹. Rapid nutrient cycling allows high water‑use efficiency and reduced energy consumption.
The Science
Primary Reaction
Ammonia (NH3/NH4+) → Nitrite (NO2-) → Nitrate (NO3-)