Restore a Fish Pond
Remove all living fish, other aquatic life and potted and free-floating plants and put them in a large plastic tub or kiddie pool with half pond water and half hose water that has been treated to remove chlorine and other chemicals.
Drain the water from the pond with a garden hose. Lay out a garden hose with one end in the pond and create suction with a pump or your mouth on the other end. Do not swallow pond water. Let the water drain as far as it can.
Use a wet vacuum to help remove the water from the fish pond. Put a long tube and a wide-mouthed attachment on the end of the suction tube and use it to vacuum sludge, silt and algae out of the bottom of the pond. You can also use a pond vacuum specifically made to help clean water gardens.
Scrub the fish pond liner, rocks and other hard decorations with a push broom or scrub brush. Remove the bulk of the algae from all surfaces as it will repopulate quickly once you set up the pond again. Combine this scrubbing with vacuuming out the water for maximum effectiveness.
Replace filter systems and pumps if they are damaged or corroded beyond repair. Otherwise, clean them thoroughly with high-pressure water from the garden hose. Filter media such as pads or floss should be replaced. It is possible that any hard media, such as bio-balls or similar, has a good colony of beneficial bacteria on it. Do not worry about scrubbing these. Simply remove accumulated sludge or debris. Use new hoses and tubes to improve water flow.
Replace the new or refurbished pump and filter back in position either inside or outside the fish pond. Put all rocks and hard decorations back in place where you want them. Refill the pond with water from the garden hose. Once the water is high enough, turn on the pump to allow the water to circulate. You can add chemicals to remove chlorine, or simply wait a couple of days for it to dissipate before reintroducing the plants and fish.
Add anti-algae, "right start" or other pond chemicals that are beneficial to a healthy pond. Solutions with bio-organisms and microbes are often recommended to help maintain water parameters and dissolve sludge and organic waste. These are all optional.
Place the aquatic plants back in the pond where they will grow the best. If necessary, purchase new plants, especially oxygenators, to improve water quality. Once the pond has sat for a couple of days with the pump running, re-introduce the fish to their new, restored pond home.