A non-dissolvable immersible dispensing puck in the shape of a dissolvable halogen puck when the dissolvable halogen puck is in an undissolved state with the non-dissolvable immersible dispensing puck physically interchangeable with a dissolvable halogen puck when placed in a dispenser for normally holding only a set of halogen pucks to enable a single dispersant dispenser to be converted to a dual dispersant dispenser without changing the structure of the single dispersant dispenser by placing a dispenser within a dispenser wherein only one of the dispensers may be provided with adjustable water ports.