The Free On-line Aquaculture Dictionary

Ammonia Nitrogen Calculations

Nitrogen production as a factor of protein fed = 6.25 x protein fed - nitrogen retained in tissues
Ammonia produced as a factor of feed fed (assuming commercial diets such as Salmonid) = 0.03 x feed weight
% unionised ammonia of total ammonia = 100 / (1 + antilog (pKa -pH))
Where
pH = pH value of sample
pKa = 0.09018 + 2729.92 / (273 + T)
T = Temperature oC
See also; Ammonia table and Nitrogen excretion calculations