In addition to outstanding capabilities for removing ammonia, it also removes heavy metals, harmful organics, all forms of phosphate and is without equal in the removal of medications after treatment. Medication such as Copper Sulphate and Formalin, Quinine Sulphate, Malachite Green, chelated copper compounds and even antibiotics used to treat bacterial infections. These substances can cause serious toxicity problems for fish after treatment since they remain in solution for long periods of time causing toxic overdosage. The "Poly Filter" rapidly removes most parasite and antibiotic medications without removing or affecting beneficial trace elements. While activated carbon and ion exchange resins have been used for antibiotic removal, many times they fail to remove the medication completely and sometimes can shock the fish. The "Poly Filter" will not shock even the most delicate fish while completely removing the antibiotics. Another important and patented feature of the "Poly Filter" is its unique ability to change a different color with the absorption of specific pollutants. It turns blue with a copper salt, light green to aqua with free copper, orange with iron, red with aluminum, yellowish green with ammonia and white to beige to brown to black with the absorption of harmful organics. This unique feature not only assures the hobbyist that the "Poly Filter" is functioning but helps him to monitor changes in water conditions and tells him when to replace the filter.