Poly Filter Poly-Bio-Marine for Fish Aquarium - Works for Freshwater and Saltwater Fish Tanks - Filter Aquarium Media Pads - 3-Pack of 4in x 8in Pads

The Poly Filter's unique chemical filtration properties offer advantages for the beginner fish owner and the experienced aquarist. Poly Filter does what other filters simply cannot when it comes to the removal of medication and antibiotics. Avoid overdose and water toxicity, Poly filter removes medication quickly as to not poison the fish, yet slowly enough to not shock the fish. The Poly Filter is unlike anything else on the market today. "It Just Makes Keeping Fish Easier!" The color guide goes as follows: red = aluminum, orange = iron, yellowish green = ammonia, light green = free copper, blue = copper salt, and brown/black = harmful organic materials.