A control which may be used for the filling of a flush tank of a commode, depending upon the amount of fluid passing through a fluid flow controlling device including a housing containing a turbine wheel. The control includes a valve actuating cam surface which is driven, through a reducer mechanism, by the rotation of the turbine wheel. The rotation of the turbine wheel is caused by the flow of fluid past the turbine wheel. After flowing past the turbine wheel, the fluid flows into a flush tank and commode. The relationship between the turbine wheel and the valve actuating cam surface is such that after a predetermined amount of fluid flows past the turbine wheel, the cam surface is rotated so as to cause the inlet valve to close.