An embodiment provides a device for mixing at least two reagent fluids, the mixed at least two reagent fluids being used for the measurement of a chemical attribute of a sample, including: a housing; at least two inlet ports, each to receive fluid in a premix state; an outlet port to dispense fluid in a postmix state; and a surface of a lumen for mixing, located within the housing, having a predetermined length, wherein the surface of the lumen is located between the at least two inlet ports and the outlet port, wherein the at least two inlet ports transition into the surface of the lumen, wherein the predetermined length is of a length allowing for sufficient mixing of the fluids received by the at least two inlet ports, wherein the surface of the lumen comprises at least one anti-siphoning element and a plurality of weirs to create a disturbance of a fluid contained therein, wherein the at least two fluids each comprise a reagent for a measurement of a chemical attribute of a sample. Other aspects are described and claimed.