Tetra Pond Fountain Block 6 Count, Controls Algae Growth In Ornamental Fountains

About this item CONTROLS ALGAE: Helps prevent algae growth in ornamental water fountains and ponds. SLOW RELEASE: Blocks fully dissolve slowly after about 10 days. FOR CONTAINERIZED FOUNTAINS & PONDS: Not recommended for containers with live plants. EASY TO USE: One block treats between 30 and 280 gallons of water. CLEARS ALGAE BLOOMS: Each block dissolves to control algae and clear algae blooms.