cartridge is not required for proper flow this ease of cartridge replacemant is important for people with limited dexterity in the preferred embodiment cartridge 12 as shown in fig3 5 includes a cartridge bottom 30 and a cartridge top 32 with reference to fig7 container 10 and cartridge 12 are shown in an exploded view both bottom 30 and top 32 of cartridge 12 are thermoformed of thin plastic material commonly used for non reusable and throw away packaging envelopes the cartridge bottom 30 includes a cone shaped wall 34 projecting inward a short cylindrical side wall 36 and an angled wall 38 connecting the cone shaped wall 34 and the cylindrical wall 36 cartridge top 32 fits into bottom 30 and is held therein by mechanical force fit by plastic welding or other low cost method the angled wall 38 includes a series of circumferential openings 40 along its surface these openings 40 may be of any size and shape which adequately allow diverted water to pass into the cartridge and allow water remaining in the cartridge to drain from the cartridge when the shower is not in use the conical wall 34 of the cartridge is truncated by.