Groundwater is commonly supersaturated with nitrogen and must be treated before it is used for culturing fish–especially sensitive species such as lake trout (Salvelinus namaycush) and Atlantic salmon (Salmo salar). We treated water with an integrated system that passed water through a packed column aerator, then through a vacuum degasser, and finally through another packed column aerator (installed as a backup system). Packed‐column aeration prior to vacuum degassing provided increased efficiency because only a small amount of vacuum was required to remove the remaining excess nitrogen, and oxygen levels were not affected by the vacuum degasser. In well water passed through packed columns, nitrogen gas was reduced from 131 to 105% of saturation and oxygen was increased from 23 to 86% of saturation. With a vacuum pressure of 3 in Hg, the degasser further reduced the nitrogen gas from 105 to 99% of saturation, and oxygen saturation remained near 86%. The integrated system provided water in which all gases were near saturation. No effects of gas supersaturation have been observed among the 18 species of cold‐water, coolwater, or warmwater fish that have been cultured in this water.
