The Airstar Filters Blue and White Bonded poly filter material is a leader in the aquatic filtration industry. The Dual-Sided filtration provides maximum filtration , while allowing your water system to operate at maximum efficiency. Blue / White Filter is a non-tackified media , which means there are no additives or  chemicals that could have an adverse effect on your aquarium / fish tank. The water passes first through the white side , which collects larger material and debris. The water then passes through the blue side which is a little denser and is able to catch the finer particulate or debris that was not caught by the white side. The Airstar Filters Blue / White Bonded Filter provides maximum filtration without restricting water flow , while helping to maintain a clear , enjoyable aquatic feature (Aquarium , Fish Tank , Pond).