EasyPro UTM1 Ultimate Tube Media for Ponds, 1-Cubic Foot Round media with multiple internal baffles which create tremendous additional surface area Each cubic foot of media covers nearly 500 square feet of surface area Ponds under-filtered will likely be cloudy, green and unattractive Very small media - Ultimate Tube Media Dimensions: 7/16" D x 1/4" L Helps keep ponds clear