In recirculating systems, what is the acceptable TAN level?

In recirculating systems, what is the acceptable TAN level?

• A. 0 ppm
• B. 25 ppm
• C. 0.5 ppt
• D. 2 ppt

Answer: (A)

Ammonia management is crucial in recirculating systems. TAN, or total ammonia nitrogen, includes all forms of ammonia in the water and is toxic to fish, especially in closed systems where waste products accumulate faster than they’re diluted. Because of this, keeping TAN at or very near zero helps prevent stress, gill damage, and mortality. In well-managed RAS, biofiltration converts ammonia to nitrite and then nitrate, while careful feeding and water management minimize production. The other numbers represent levels far above what is safe in typical operating conditions, and would pose significant risk to the fish. So the best approach is to maintain TAN at zero parts per million.

Ammonia management is crucial in recirculating systems. TAN, or total ammonia nitrogen, includes all forms of ammonia in the water and is toxic to fish, especially in closed systems where waste products accumulate faster than they’re diluted. Because of this, keeping TAN at or very near zero helps prevent stress, gill damage, and mortality. In well-managed RAS, biofiltration converts ammonia to nitrite and then nitrate, while careful feeding and water management minimize production. The other numbers represent levels far above what is safe in typical operating conditions, and would pose significant risk to the fish. So the best approach is to maintain TAN at zero parts per million.