Abstract: An applicator for allowing a predetermined flow of a fluid for dissolving and distributing soluble substances comprises of a cap and a hollow cylindrical housing. The hollow cylindrical housing comprises of an enlarged chamber having a narrowed inlet port at its lower end. The narrowed inlet port has external threads connecting to a Tee pipe fitting of a pipeline of a fluid system and has a cylindrical flow channel extending to the enlarged chamber. The cylindrical flow channel has six equal V flow passages which are constructed by six vertical dividing walls locating at equal spaces around the wall of the cylindrical flow channel and extending inward to the axis of the cylindrical flow channel. The six equal V flow passages have six equal vertical openings which are constructed by the vertical dividing walls and disposed outside the cylindrical flow channel of the narrowed inlet port at a predetermined length. The six equal vertical openings comprises of three vertical inlets and three vertical outlets.