DIY biofilter for a small fish pond

DIY biofilter for a small fish pond
Photo provided by Flickr
Waterfall Filters
Perfect for: Large ponds with many fish
Designed for small, medium or large ponds, provide a big waterfall display while biologically filtering the water. The pond water flows up through the filter media, where the beneficial bacteria clean the water, then spills out to create an elegant water display. They’re great for new ponds and easy to install in existing ponds and water gardens. They don’t offer the UV filtration, but they typically filter more water, handle larger pumps and won’t plug up as easily.
DIY biofilter for a small fish pond
Photo provided by Flickr
Read up on the oxbow effect. It is how a natural pond is made. Patience and time is all that is needed. I have 5 ponds of differing sizes and none of them have pumps or filters. Just plants and fish. They went thru a small adjustment as they settled, but now are clear and nice. Pressure filters are ideal stand-alone filters for small to medium koi/fish ponds
Photo provided by FlickrI have experience building a small goldfish pond without a filter system, but I know that koi ..
Photo provided by FlickrDIY biofilter for a small fish pond ..
Photo provided by Flickr
Your water feature's pond pump filter is the most important part of the overall pond. The design, plants, rocks, and even fish can add some great attractive qualities, but no functional purpose. The pond pump and filter serve the main purpose of moving the water and keeping it clean.

Choose the Right Size

Often times, people building a pond in their backyard choose the wrong size pump for their needs. Pumps have a large job that can overwhelm a pump that is too small. A pond pump filter needs to be able to circulate water through a screen-type filter to another filtration tank outside of the pond itself. Then the water is returned through another pipe, usually ending up in a waterfall feature. Most pumps, even ones that are packaged with a pond kit, cannot adequately handle the correct rate that the water must be "changed."

Changing the water refers to circulating the entire capacity of the pond through the filtration device, thus cleaning the entire pond. However, with biological debris and other debris blown in by wind, the pump does not just have to push along water. A typical "change" rate should at least 4 to 5 times an hour. If your pump does not do that now, then you should look into larger pumps.

Construct Filter Box


Your filter is not going to go into the water, so it must be placed in some sort of attractive container or a constructed box. You can hide this with plants or rocks if you choose. This container then goes to the side of the pond, on the farthest end from where you will place the pump.

Connect the wire to the electrical box by running wires, through a plastic PVC conduit underground, from the filter to the electrical supply. Then using hose clamps, you can connect both the inlet hose and the outlet hose, putting both in place where they are going to be hidden from sight.

Install Pump

Run water into the pond until the bottom is covered. This will help you get rid of wrinkles in the liner and show you any low spots. After filling in these spots, and fixing liner, you can place the pump on the bottom of the pond. Your pond pump filter can either be set out freely, or put into a water safe container for aesthetic purposes.

Connect the hoses to the pump to send water to the filter, and begin filling the rest of the pond. After the water is finished filling, plug in the pump, and check to see if the water is running freely (without any clogging or suction noises).

Add Plants and Fish

The major attraction to any pond is not the pond pump filter. It is the plants and fish that you put into it. Let the pump circulate the water for a few days to get rid of any debris from construction and to check the "change" rate. Once everything is set on the pump and the pool, add your biological elements and enjoy.These filters include those from Pondmaster or may be a homemade bucket filter. While these filters are usually inexpensive and easy to install, maintenance can be a struggle. To clean, you must reach down into the bottom of the pond to retrieve the filter, then pull out the media. In-pond filters are usually installed by the homeowner. Professionals will avoid these except on very small ponds with low fish stocking.If you are building a waterfall that is mainly to be enjoyed for the sound and beauty of the waterfall itself with no fish and a small pond or disappearing water feature, it would be silly to install a large biological filter. About the only filtration you may need is one to remove particles from the pond. A prefilter or canister filter may be all that is needed. And if your project is to build a koi pond then you better make sure to include plenty of biological and mechanical filtration. You may well want to use an ultraviolet sterilizer as well.Believe or not, you can over-filter a pond. Tight filter pads in your skimmer pick up the smallest particles of debris, causing you to be cleaning the filtering mechanism out constantly. Fish in the wild certainly don't swim around in bottled water. If you can see a dime on the bottom of the pond, then the water clarity is just right for your fish and filtering past that create headaches, not eliminate them.