Many people depend on their pond filtration devices to clean the silt and debris out of the pond water, but over time the filter can't keep up with all the debris and the pond liner will begin to build up with silt. Your pond liner should be cleaned at least every five years. A pond with fish should be cleaned during the spring and a standard water-filled landscaping pond should be cleaned during the fall.
Skim off any algae or debris off the top of the pond with the pool skimmer net. Put the debris in the trash can.
Place the fish tank in a cool, shady location. Fill a bucket full of the pond water and dump it in the fish tank. Use the fish net to grab the fish, if any, from the pond and place them in the fish tank.
Plug the pond vacuum in and turn it on. Insert the vacuum hose into the bottom of the pond. Work your way from the outer edge of the pond toward the deeper center of the pond. Focus on sucking up all the silt, weeds and fish feces covering the liner by running the vacuum hose flush along the pond liner to ensure you remove all the waste and debris.
Shut off and empty the pond vacuum tank when it gets full and dump it in the trash can. If you sucked up too much water in the process of cleaning the silt from the pond liner, add water to the pond, using the hose, until it reaches the level you want.