Abstract: A set of bottles for containing dialysate chemical formulations, chemical cleaning agents or the like is described. The chemical formulation bottles come in two varieties, sodium bicarbonate and liquid acid formulations, each bottle having a slightly different shape. The different shapes cooperate with a bottle mounting structure in the dialysis machine to insure that bottles are correctly installed on their respective bottle opening mechanism. The bottles also have a detection feature comprising either a raised rim or groove extending around the periphery of the bottle. A sensor assembly in the bottle mounting and opening system detects the detection feature. The detection feature is used by the machine to distinguish between dialysate formulation bottles and chemical cleaning bottles, which do not have the detection feature. The detection feature prevents unintentional installation of the chemical bottle on the opening mechanism for the dialysate chemical formulation bottles.