Why spend money on expensive pond filters when you can make your very own DIY filter for your koi pond at home? There are many different DIY plans to choose from when it comes to making your pond filter and most of these methods require affordable items that you might even already have around your home.
If you have an outdoor pond for koi, part of the challenge to maintaining a beautiful pond is keeping the water crystal clear enough to see the koi swimming through the water. Most commercial pond filters are overpriced and require a lot of maintenance, which can take the joy out of keeping a successful koi pond.
With a little bit of patience and lots of creativity, you can create a pond filter for your koi that is the right size for your pond, has a unique appearance, and most importantly, works efficiently to keep your koi pond clean and filtered.
Table of contents
The 10 DIY Koi Pond Filters You Can Build Today!
1. Storage Tub Filter
| Materials: | Large storage tub, foam sheets, plastic piping, pump |
| Tools: | Carving tool, scissors |
| Difficulty: | Beginner |
This filter is inexpensive, and the foam sheets can be purchased from your local pet store near the pond section. You may already have a large unused storage tub lying around which will form the basis of the filter and hold the media inside. You’ll need to carve two separate holes at the top of one side to connect the plumbing system so it can be connected to your pond.
This plan offers mechanical and biological filtration, as the foam sheets will trap in dirt and debris that would otherwise cloud your pond, while also providing a large surface area for nitrifying bacteria to grow.
2. Hose Pipe & Tub Filter
| Materials: | Large storage tub, piping, hose pipe, pump |
| Tools: | Carving tool |
| Difficulty: | Intermediate |
This filtration plan is slightly more complicated but very effective at running a good filter system through your pond. You will need to find a good placement to run the hosepipe through the tub to create a flow. Stones can be placed inside the tub to weigh the tub down, and you also can grow plants in the stones to make the filter look more attractive. If you do add plants to the top, they will use the nitrates from the pond water to grow, creating a balanced aquaponic system. The irrigation pipes can be purchased from your local hardware store and bolted into the large tub.
3. Bioactive Pond Filter
| Materials: | Large storage tub, filter media, plastic sheets, pump |
| Tools: | Carving tool |
| Difficulty: | Beginner |
This bioactive filter is a great way to use mechanical, biological, and mechanical filtration to keep smaller ponds crystal clear. The main materials you require to create this DIY filter are an assortment of filer media in bulk, such as activated carbon, bio-cubes, and square pieces of foam. The water will run through the irrigation pipes, through the piece of square foam which will catch debris and dirt, and finally through the filter media for chemical filtration. This is a great idea for small koi ponds where you are struggling to keep the water clean.
4. Stacked Tub Method
| Materials: | 3x large storage tubs, piping |
| Tools: | Carving tool |
| Difficulty: | Beginner |
This filter plan has a lot of potential to filtrate large koi pond systems, even though it’s somewhat bulky. It also doubles as an aeration method because the water flows through a slit in the bottom tub and works like a waterfall. The tubing runs through all three of the tubs, which allows this DIY filter to filter a large volume of water at a time.
You have the option of choosing what you want to place in the tubs, and you can use each step of filtration (mechanical, biological, and chemical) in each tub. For example, you can place foam sheets in the first tub for mechanical filtration, filter media in the second tub, and more foam sheets in the third tub.
5. Waterfall Storage Tub Filter
| Materials: | Large open tub, pipes filter media, pump |
| Tools: | Carving tool |
| Difficulty: | Beginner |
This is a simple DIY koi pond filter. You’ll need to purchase a pump and a very big tub to get started. Carve a slit into the top of the tub where the water will pour out and cut a square in the lid to stick underneath the slit to achieve the waterfall effect. The pump will run from the pond and through to the tub which will have your desired filter media in, and then be pushed out of the filter bowl. You also have the option of adding a valve to control the water pressure so you can adjust the settings until the flow is right for your koi pond.
6. Bucket Method
| Materials: | Bucket, lid, pipes |
| Tools: | Carving tool |
| Difficulty: | Beginner |
This is a simple DIY pump ideal for beginners. One pipe is connected to the top of the bucket where it will flow inside the bucket and through the filter media you choose to put inside and then filtered back into the pond. This is a good idea for small ponds, and the size of the bucket will depend on the size of your koi pond, so you can be creative with what you choose to put into the bucket and the size and color option you choose.
7. Large Barrel Filter
| Materials: | Barrel, pipes, valve, pump |
| Tools: | Carving tool |
| Difficulty: | Beginner |
This pond filter works with a valve that will suck up old pond water and run it through a barrel, which can be filled with netting at the top to catch large debris such as leaves, and then through a foam or filter wool to catch the smaller dirt, and then to filter media of your choice. The filtered water will then run to the bottom and out of the bottom piping to replenish the pond with clean, filtered water.
8. Small Pond Filter
| Materials: | Tall plastic tub, filter media, piping |
| Tools: | Carving tool |
| Difficulty: | Beginner |
This is a simple and by far the easiest DIY pond filter you can make for small koi ponds. All you need to get started is a tall plastic tub of your desired size and lots of different filter media. You can choose media such as foam sheets and bio-cubes for chemical, biological, and mechanical filtration. The bottom of the tub has a pipe where the filtered water will return into the pond, and you can simply run a small pump to ensure that the old pond water is reaching the top of the tub to be filtered through the media.
9. DIY Fish Pond Filter
| Materials: | Storage tub, foam sheets, filter wool, piping, pump |
| Tools: | Carving tool |
| Difficulty: | Beginner |
This filter works by suctioning up water from the pond and running it through the storage tub, which is full of filter wool, but you also have the option of adding filter media (such as activated carbon and bio-cubes) to the bottom for chemical filtration. The filter wool provides a place for nitrifying bacteria to grow which will ensure that the water returning to the pond through the output pipe is filtered and fresh.
10. Sponge Pond Filter
| Materials: | Tub, dish sponges, long narrow tube |
| Tools: | Carving tool |
| Difficulty: | Beginner |
This is a beginner-friendly DIY koi pond filter for small ponds. The logistics are simple to understand and not much work is required to make this filter work. All you will need is a round tub with a lid, which can be found in your home or purchased from a store, and tubing which will go through a hole carved in the middle of the lid.
The main type of filtration for this system is from the dish sponges which should be filled in the tub. This is a great way to biologically filter your koi pond because the sponges provide a breeding ground for beneficial bacteria.
Final Thoughts
There are so many creative ways to make a DIY koi pond filter! The type of filter you choose should be easy for you to create and install while providing enough filtration for the size of your koi pond. If you are struggling to keep your pond clean because debris and leaves are falling into the pond, then you’ll want to choose a DIY filter that has netting or foam sheets to catch this debris. If you have a small pond, then a small return valve filter may be a good option for you.
Featured Image Credit: NatalieStamer, Pixabay
