Water Filter Cartridge (Aries Filter Works) ORGANICS/TANNINWater Filter Cartridge (Aries Filter Works) Organics Tannin Tannins and similar naturally occurring organic cause most of the color in potable water. They tend to discolor water and give it a bitter taste. They are non toxic and are harmless to humans. However, their presence can make well water unpleasant to drink and stain laundry. Aries uses ResinTech SBACR onion exchange resin to remove Tannins. Prices subject to change due to inflation. Price