The koi pond’s shape is approximately a quarter of a circle with a radius of 15 feet, bordered on one side by a waterfall and the other by four chambers, covered by a redwood deck. The water continuously flows down a drain in the bottom of the pond and goes up in the first of the chambers. This chamber serves as the residue chamber and cascades into the next three chambers. Chambers 2 and 3 are the bio-filters with good bacteria that keeps the water clean and healthy for the fish. The forth chamber (lowest point) serves as the reservoir for the one-fifth horsepower pump. From the pump, the water flows six directions as controlled by six valves. Three small valves control the circulation of the water in the main pond through jets under the surface of the pond. Three larger valves control the flow of separate waterfalls that converge into the main pond. The highest waterfall flows through the upper pond, located in the upper left-hand corner of the photo below.

Both the upper and main pond have a thick black rubber liner. The maximum depth in the main pond is five and half feet. This protects the fish from the raccoons that visit every night and provides a large volume of water so the Koi can grow to maximum size. The total volumn of water in the system (ponds and chambers) is over 5,000 gallons. The pump works 24 hours a day and the turnover rate is about 14 times a day. That's how many times a day all the water is circulated through the filter and pump.

The photo was taken from the sliding-glass doors in our bedroom, pointing toward the arbor. From front to back, the features are the bedroom patio, the main pond and waterfall, the bridge over the waterfall, the main walkway (behind the top of waterfall), the block wall behind the walkway, the arbor above the block wall, and the wooden steps up the hill behind the arbor.

The Koi shown were photographed at night against the black background of the pond liner. The originally posted photo was taken during the day and the overhead background always reflects on the surface. So the idea of using a flood-light at night was tried last night. The results were much better.