A deaerator includes gas nucleation media and a porous barrier. The deaerator may include growth media between the gas nucleation media and the porous barrier. The deaerator may be part of a system for removing gas from a fluid, where the system includes a tank with a fluid inlet and a fluid outlet and having a fluid flow path from the fluid inlet to the fluid outlet, and where the deaerator is in the fluid flow path. A method for removing gas from a fluid includes passing the fluid through the deaerator defining a fluid flow path.