A chromatography system has an associated system volume and a sample dispersion volume. The chromatography system comprises a pump pumping a flow of gradient, a sample manager for introducing a sample into the flow of gradient, and a valve manager fluidically coupled to the pump and to the sample manager. The valve manager includes at least one valve. A first valve of the at least one valve has a plurality of ports including an inlet port that receives the flow of gradient from the pump and an outlet port through which the flow of gradient exits the first valve. The first valve has at least two different, automatically selectable positions. A first position of the at least two different automatically selectable positions operating to change one of the system and sample dispersion volumes of the chromatography system when the first valve is automatically switched into the first position.