Black Waterfall Foam Black Waterfall Pond Foam is a type of expandable foam that is used for waterfall, stream and pond construction. Use it between rocks to make water flow where you want it to. This black expanding foam makes it possible to easily tweak out your waterfalls and stream by directing where the water flows. This will help your get the best waterfall effect by making the water flow over the rocks rather then underneath them. It's also used to secure rocks on the lip of the Biofalls filter and around the pond skimmer. 16 oz. ponddepot@msn.com Copyright - All World Rights Reserved Pond pumps, Pond Kits and Pondless Waterfall kits, Underwater Pond Lights. Aquaclearer Extreme bacteria and String Algae Buster and pond fish food. Pond Depot provides Do-it-yourself pond kits and Pondless waterfall kits delivered right to your home at great prices! Thank you for shopping at Pond Depot you online pond superstore!