Building a Koi Pond Filter

Building a koi pond filter is an easy project that should take under an hour to complete. Koi ponds have one of two types of filters and sometimes both if conditions call for it. The two types are mechanical and biofilters.

You will want your koi pond filtration system to be efficient in cleaning up the pond continuously. If a pond is allowed to get too murky, it will take longer to clean it and two pumps might be a requirement instead of a choice. You might have everything in your home that it takes to build a biofilter.

Step 1 - Drill The Holes

You are going to need to drill two holes in a storage container. You will need one that is lower that will snuggly fit the length of the hose that will drain to the pool and one that is smaller that fits the output hose on your small pump.

The draining hole should be lower because the water is going to enter through the smaller hole via the pump then filter through the sponges and into the output area of your filter.

Step 2 - Place The Brick

The next thing that you need to do is place the brick at the bottom of the container. This will help to create a place for the gunk to collect as well as a shelf for your sponge filter.

Step 3 - Wire Rack

The next piece that goes in is the hardware wire that is cut to fit inside the container. You will place this on top of the brick so that the sponges have a stable resting area.

Step 4 - Fill And Place The Bag

Fill the mesh laundry bag until it will not fit any more sponges. Then place the sponges on top of the wire mesh shelf. The pump hose should be dumping directly into the sponges.

Another good idea for your filtering agent is a heater or cooler air filter. Cut it into squares that fit snuggly into the container.

Step 5 - Test It

Plug in your pump and start pumping water through your filter. The water will flow through the sponges then into the bottom of the container. The water will rise and start to flow out of the exit tubing. Be sure to not let this hose rest on the bottom of the container or a lot of the much will return to the pond. Set your pump to the lowest setting at first to test for how fast the water circulates through the filter.

Once you have tested and made any necessary adjustments, then it is time to leave the filter running to do its job cleaning the pond. Check the filter daily to make sure that it is functioning properly and not causing any damage. If you are still experiencing filtering problems, consider adding a mechanical filter to aid in cleaning the koi pond. With trial and error testing you are sure to find the right combination for your pond.