a second fastening device for temporarily securing the cartridg e dispensers 13 to the holder 11 an advantage of having a removable cartridge is allows one to provide for interchanging cartridge dispensers or to allow one remove and replace a spent cartridge dispenser this feature is particularly beneficially when one of the materials within the cartridge dispenser has a longer dispensing life than the other consequently only the spent cartridge dispenser needs to be replaced rather than the entire system in the preferred embodiment when used in water treatment the floating dispenser system 10 can hold two different dispensing materials to aid the user in identifying the cartridges containing the different dispensing materials when the cartridge dispensers have the identical shape and size one can color code the cartridge dispensers for example one cartridge could be a blue mineral cartridge 12 which yields ions and the second cartridge could be a yellow bromine cartridge 13 which yields bromine the color coding permits a user to quickly identify the contents of the cartridge and the purpose of the cartridge dispenser to replace a spent cartridge the user merely removes the spent dispenser cartridge out of the holder and secures a fresh cartridge into position 0024 fig4 shows a top view of the.