A fluid control system comprising: an outlet valve assembly; an inlet valve assembly including a venturi inlet valve; an actuator coupled to the inlet valve assembly, the actuator configured to enable a user to control and adjust a flush volume of the fluid control system; a moveable float positioned in a chamber of the outlet valve assembly, the chamber including a variably-sized upper portion, wherein the volume of the upper portion is based at least in part on a variable position of the moveable float in the chamber; an adjustable first control valve coupled to an outer surface of the outlet valve assembly, the first control valve being fluidly coupled to the inlet valve assembly; an adjustable second control valve movably coupled to an outer surface of the outlet valve assembly, the second control valve fluidly coupled to the inlet valve assembly; and a bellows positioned in and coupled to the variably-sized upper portion, the bellows fluidly coupled to the venturi inlet valve and at least one of the first and the second control valves, wherein the first control valve comprises an inverted cup coupled to a channel that is fluidly coupled to the inlet valve assembly, wherein based on a position of the first control valve on an outer surface of the outlet valve assembly, the first control valve is configured and arranged to control access of at least a portion of the inlet valve assembly to an open atmosphere based at least in part on an initial fluid level of fluid in a reservoir in which the fluid control system is at least partially positioned, wherein the second control valve comprises an inverted cup coupled to a channel that is fluidly coupled to the inlet valve assembly, wherein based on a position of the second control valve on an outer surface of the outlet valve assembly, the second control valve is configured and arranged to control access of at least a portion of the inlet valve assembly to an open atmosphere based at least in part on a residual fluid level of fluid in the reservoir in which the fluid control system is at least partially positioned, wherein at least a partial vacuum created in the bellows by a fluid flow through the venturi inlet valve from a supply line enables the moveable float to lift to a least partially cover an input port to an outlet valve resulting in a slowing or stopping of the fluid flow from the supply line. an outlet valve assembly; an inlet valve assembly including a venturi inlet valve; an actuator coupled to the inlet valve assembly, the actuator configured to enable a user to control and adjust a flush volume of the fluid control system; a moveable float positioned in a chamber of the outlet valve assembly, the chamber including a variably-sized upper portion, wherein the volume of the upper portion is based at least in part on a variable position of the moveable float in the chamber; an adjustable first control valve coupled to an outer surface of the outlet valve assembly, the first control valve being fluidly coupled to the inlet valve assembly; an adjustable second control valve movably coupled to an outer surface of the outlet valve assembly, the second control valve fluidly coupled to the inlet valve assembly; and a bellows positioned in and coupled to the variably-sized upper portion, the bellows fluidly coupled to the venturi inlet valve and at least one of the first and the second control valves, wherein the first control valve comprises an inverted cup coupled to a channel that is fluidly coupled to the inlet valve assembly, wherein based on a position of the first control valve on an outer surface of the outlet valve assembly, the first control valve is configured and arranged to control access of at least a portion of the inlet valve assembly to an open atmosphere based at least in part on an initial fluid level of fluid in a reservoir in which the fluid control system is at least partially positioned, wherein the second control valve comprises an inverted cup coupled to a channel that is fluidly coupled to the inlet valve assembly, wherein based on a position of the second control valve on an outer surface of the outlet valve assembly, the second control valve is configured and arranged to control access of at least a portion of the inlet valve assembly to an open atmosphere based at least in part on a residual fluid level of fluid in the reservoir in which the fluid control system is at least partially positioned, wherein at least a partial vacuum created in the bellows by a fluid flow through the venturi inlet valve from a supply line enables the moveable float to lift to a least partially cover an input port to an outlet valve resulting in a slowing or stopping of the fluid flow from the supply line.