A method for mixing a fluid includes: dispensing a first volume of a fluid into a flexible container, the flexible container being at least partially disposed within the chamber of a support housing; repeatedly moving the support housing and the flexible container contained therein so as to mix the first volume of fluid within the flexible container; adding further fluid into the flexible container after moving the support housing to form a second volume of fluid; and manipulating a mixing element within the flexible container so as to mix the second volume of fluid.