The present invention is directed to degassing devices for dialysate circuits.One embodiment has a first housingand a second housing positioned within the first housing in an annularrelationship. A second embodiment comprises a dialysateregeneration system with urease, a dialyzer, and a housing with an externalwall, where the external wall is exposed to atmosphereand comprises a material that passes gas but does not pass liquid and wherethe housing is positioned between the urease and dialyzer.