Make Your Own Pond Filtration System
Rinse out a large plastic tub, such as a Rubbermaid storage container, with clear water from the hose. Also rinse all other materials, such as PVC pipe or tubing and the filter media you chose. Determine where you will place the filter in the pond and what side you need to attach the pump to.
Cut a large rectangle out of the top of the plastic container. If you are using a covered bucket, the hole can be a circle, but should remove most of the lid to the vessel. Also cut a hole in the side of the filter container near the bottom edge. This should be the correct size to fit the piece of PVC pipe you bought for the pond filter.
Use a hacksaw or other hand saw to cut a piece of PVC pipe approximately 4 inches long. Cut another one long enough to reach from the filter to the pond pump. Put the short piece into the hole in the side of the filter box and use sealant to affix it firmly in place. Attach the other pipes together as needed with elbow turn pipes to get them into a convenient position to accept the intake hose from the pump.
Place a quantity of small rocks in the bottom of the plastic pond filtration vessel. These will not only help weight the filter to keep it in place, but will provide a home for beneficial bacteria colonies to grow. The rocks should not be too small, otherwise they will impede water flow.
Top the rocks with plastic wiffle ball golf balls or a similar material. These act as "bio-balls" such as are used in expensive filters. They are optional, but do provide space for bacteria colonies to establish. Complete the internal filtration with a porous pad of quilt batting or a similar material. Purchasing approved filter media from a pond supply catalog or store is another option.
Cut a piece of window screen material large enough to cover the entire opening of the plastic container. This will be the first layer of filtration material that will stop large debris from clogging the filter or pump. Lay this over the entire opening of the plastic tub and snap the lid on over it to hold it in place. The home-made pond filtration system is ready to sink into the pond and attach to the pump.