The effect of Alliance, a manure pit additive was tested in 4 commercial grow-finish barns for a period of 6 months. This ammednment produced an average 24.2% reduction in ammonia levels relative to the control. The treatments saw a range of 12.5 – 27.3% reduction in amonia concentration over both trials.. With the use of this pit amendment it was also noted the importance of keeping the floor as dry and clean as possible. Ammonia reduction rates were found to be greater in the second trial by approximately 10%, this difference may be realted to the season variation of gas emissions from swine buildings. There was evidence of dilution with the addition of the pit amendment. However, the addition of the pit additive did not affect th pH of the manure. As a result the lower concentration of ammonia in the traeted buildings may have contributed to the lower ammonia emissions.