Abstract: A dilution reservoir (10) with one or more channels (30) is provided in which the channels (30) are easily accessible and which allow improved material manipulation. The dilution reservoir (10) includes a housing (14), having a base (18), a top (16) opposite the base (18) and a plurality of sides (20), (22). One or more channels (30) are located in said housing (14), each channel (30) having a mouth (40) at the top (16) of the housing (14) which opens into a cavity (38). Each channel (30) and each cavity (38) has a longitudinal axis (44), a transverse axis (48), a depth axis (46), and the channels (30) have arcuate cross-sections. These arcuate cross-sections provide true low points (60) in the bottom (56) of each cavity (38) which facilitate collection of material. The mouths (40) of the channels (30) are elongated in the direction of the longitudinal axis (44) thus allowing a wider range of access angles (78) for insertion of a standard pipettor.