Making a natural pond filter with sand and gravel is an environmentally friendly way to keep pond water fresh. This is important whether the pond contains fish or not -- without a filtration system, the water will become stagnant. Ponds are a common garden feature that contain small decorative plants and often ornamental fish. In addition, many ponds also contain rocks, fountains, streams and waterfalls. A natural pond filter will go a long way towardss keeping a pond fresh and aesthetically pleasing.
Clean all materials thoroughly with hot water to remove any residues that could pollute the pond.
Cut a hole with the utility knife 7.5 cm (3 inches) from the bottom of the plastic bucket wide enough to fit the PVC pipe through. Cut a large circular incision in the centre of the bucket's lid as a pond water entry point.
Cut a 90 cm (3 feet) length of PVC and insert it 7.5 to 10 cm (3 to 4 inches) deep into the bucket. Seal around the pipe with waterproof silicone. Attach a 1.8 metre (6 feet) hose to the outside end of the PVC pipe with a hose connector.
Cut a piece of mesh screen large enough to fit over the top of the bucket.
Fill the first third of the bucket with gravel. Fill the second third with sand. Leave the top third empty for water and place the screen across the top. Snap the lid firmly onto the bucket.
Connect the hose to a pond water pump and place both the filter and pump into the pond. Wait for it to stop bubbling, which signals that the sand and water filter is full of water. Switch on the pump.