Heron & Critter Protection Netting, 2" Mesh Popular but you will also need Size:Small Starter Pack WITH 8oz dechlorinator but you will also need a new locking assembly as the one you have now will not fit over two filter chambers SKU Pond Size Liner Size Pond Size Pump Flex Pipe Wt EM1116FB 11' x 16' 15' x 20' 2000 gallons TH250 2" x 25' 290lb EM1616FB 16' x 16' 20' x 20' 2900 gallons TH250 2" x 25' 310lb EM1621FB 16' x 21' 20' x 25' 3800 gallons TH400 2" x 50' 370lb EM2121FB 21' x 21' 25' x 25' 4950 gallons TH400 2" x 50' 400lb EM2126FB 21' x 26' 25' x 30' 6150 gallons TH400 2" x 50' 430lb It is also possible to use a large beach ball or other floating object to create a tenting affect to further aid leaves blowing off of the cover instead of collecting on the cover Virtually invisible