You are purchasing a 1kg bag of high quality bacterial balls (2 x 500g). Our bacterial balls are ideal for aquarium and pond filters. These bacteria balls are packed in mesh bags - they are easy to clean in the filter. Additionally, they can be removed from the bag and placed in a filter. The large surface area allows beneficial bacteria to colonize and biofilter the water removing ammonium and nitrites. Note: You will receive two 500g mesh bags which means each bag will have 500g. Contents: 500 gx 2 (mesh packet). Compatible with: freshwater, saltwater and grass nitrate farming. Product Features: Bacteria play high efficiency in the filter. The pore structure can be a good breeding ground for nitrifying bacteria, creating good water quality and reducing the frequency of water changes.