The photo above is looking down into the "pit," which is now covered with a sloped roof to look like a storm cellar on the side of the house. It is the "heart" of the filtration system--a part that is hidden from view, but extremely important. The large tan-colored box is called a "sieve." Water exits the lower pond via the bottom drain and the overflow, and flows to the pit underground through the two largest (4") pipes you see on the bottom left of this photo. The sieve is positioned in the pit so that water in the left compartment will always be level with the water in the pond, because the two are connected with the large pipes. If the electricity goes off, the water will flow through the pipes until the water "levels out" between the pond and the sieve, and then it just sits there.
The pump is small and black, located near the upper right corner of the photo. Once the electricity is turned on, the pump begins to draw water out of the sieve, and up through the three white pipelines above it (see the one pipe that splits into three?). Each of those three pipelines goes through various types of filters before the water returns to the pond. The pump moves about 7500-8500 gallons per hour, so water is quite rapidly flowing in and out of the sieve. (By the way, it consumes about 333 watts of electricity--so the whole pond is powered with about the same amount of electricity it takes to light three 100 watt light bulbs.)
In the sieve, the water passes through a special curved "screen" that catches all but the smallest particles in the water. The material that is removed from the water by the sieve can easily be removed by hand.
One branch of the pumped water squirts directly back into the bottom pond in order to create a circular flow of water in the pond and help move debris to the drain. Another branch goes through a series of 55 gallon barrels in the fenced in area next to the pit, and then flows back into the pond by gravity. The third branch is pumped "uphill" through two "sand/gravel" filters that help catch any tiny particles left in the water before flowing into the top pond.
Once the top pond fills up, it simply "overflows" via waterfalls into the middle pond, and likewise, once the middle pond fills up, it flows into the bottom one, where the process begins again.
Q: What are "Koi?"
A: Koi are a special type of carp that hobbyists, beginning with the Japanese centuries ago, have bred for color and size and "show quality." They can reach a length of at least 3 feet, and live for many decades. Some (not ours) even have "papers" to certify their bloodlines and relation to certain prize-winning fish. Such fish can be worth tens of thousands of dollars; ours are more common, but still beautiful and growing fish.
Q: Did you buy these when they were big or small?
A: I have recieved several larger ones free or cheap from a friend who needed to thin out his collection, but the rest I have raised from small fish about 2-4" long. The largest one in the pond is now about 28" long.
Q: In the top pond, are the smaller fish baby koi?
A: No, the top pond contains goldfish; a relative of koi, but a different species. Koi have "whiskers" and goldfish do not. Goldfish also grow to a maximum size of about 12", while Koi can grow to more than 36". Because Koi eat and uproot plants, their pond does not contain any plants, but we can safely put plants in the top two ponds with the goldfish.
Q: How deep is the pond, and how many gallons does it hold?
A: The two large basins are about 40 inches deep in the center, and altogether, the three connected ponds plus the filtration system holds almost 10,000 gallons. Once it is full, it would be rare to completely empty the pond--usually just a small amount of water is replaced at a time as part of routine maintenance.
Q: What do you do with the fish in the winter?
A: Koi and goldfish quit eating when the water temperature drops below 50 degrees. They get sluggish, and hang out near the bottom. They are not "hibernating," because they do not sleep, and they do continue to move around slowly, even under the ice. We build a wood frame and cover the lower (koi) pond with clear plastic--that prevents the water from freezing, and lets the pumps keep circulating the water all winter. The goldfish are smaller, and less likely to be harmed by living under the ice. So we just put a bubbler in their pond and that keeps an open hole in the ice most of the winter to keep plenty of oxygen in the water.
Q: Is it hard to maintain the pond?
A: No, it was designed with an elaborate but easy-to-maintain filtration system. It does not require daily care, and there are some seasons you can ignore it all week without any problem, except throwing a little food in to the fish every day or two.
Q: Did you design and build this yourself? How long did it take you? How did you construct it?
A: Jeff designed & built the pond and filtration system, going through numerous versions for almost a year before we "broke ground" in the spring of 2011. Several others helped at key times, including Shelly and our sons, Evan Heins who used a backhoe to dig out the basic shapes of the ponds, and Don Steinkuhler who dug the trenches for the underground water lines. Our neighbor, Caden Tunis, helped with some of the hand digging, and also helped us drag the extremely heavy rubber liner into the holes. The pond was functioning with happy fish swimming in it by that fall, three months later. Shelly spent most of the 2012 spring and summer working on the plants and landscaping around the pond.
See the series of photos to the right to get an idea of the progression of the project during that first summer of 2011.