Abstract: Described is a device for introducing substances into water. The device includes a housing (1) forming first and second chambers (7, 9) separated by a partition (8). Throughgoing housing openings (11, 12) are provided on either side of the partition to allow each chamber to communicate with the container (21) supplying the substance. A connecting flange (15) having throughgoing flange openings (19, 20) is provided for connecting the housing to the container. The flange is arranged turnably relative with the housing such that in an operative condition each throughgoing housing opening coincides with a respective throughgoing flange opening. The turnable arrangement also includes at least one pin (17) located on the flange and which engages at least one groove (88) formed in the housing. A controlling means (24) is also provided in an opening (25) of the partition.