CrystalClear Polish AC is a bituminous coal that has been exposed to extreme heat which "activates" the carbon, giving it a powerful absorbing ability. The billions of pores within the pelletized natural carbon act as hundreds of sponges soaking in and removing many pond pollutants such as tannins, ammonia, nitrite, and nitrate. Carbon also acts as a deodorizer, helping to control any foul smell. The result is a polished, pristine, cleaner aquatic environment. Treatment is perfect for any freshwater outdoor pond, water garden, aquarium - or even in large fishtanks. For Routine Applications. Clean bag and add new Polish AC carbon every 3 months. Simply remove the provided bag and scoop in the appropriate amount of carbon substrate for your pond size or filter size. Then rinse the bag thoroughly to clean and remove any carbon dust. Then apply to filtration unit. It is always best to use Polish AC in conjunction with a filter. It is not recommended to use Polish AC by itself within the pond. It is important to maintain fresh activated carbon especially throughout the spring and summer season when pond pollutants are at their highest levels. When you first apply treatment, water may be cloudy from loose dust; this is normal and will clear quickly. No temperature restrictions - use all year. For Persistent Problems: For reoccurring problems and large fish loads, double the amount of carbon for the pond size. When used as directed, treatment will not harm any animal, frog, goldfish, koi, bird, turtle, pet, reptile, snail, dog, horse, or plant. Will not harm your waterfall pump, skimmer, aerator, filters, clarifier, purifier, detoxifier, conditioner, fountain, or accessories. Polish AC is an easy-to-use treatment made for polishing pond water. CrystalClear offers many premium pond cleaning products and solutions to help fix your pond problems, from natural treatments to chemicals.