What I will repeat
My pond is roughly 4000 US gal and only has 6 koi in it. There are a lot of different stocking ideas, but even by the most conservative levels, my pond is understocked. As a result of this, I have never dealt with disease. The next time I have a pond, it will most certainly have no more than one koi per 500 gallons.
I built my pond on the edge of a forest. Granted, this did make the actual construction a bit of a hassle, but the end result is a wonderful canopy of leaves that cover my pond. Despite the temperatures commonly soaring above 90F at my house, the water never got warmer than 80F. The canopy also shields my pond from herons. I live less than a mile from a river and have never had problems with them. The only problem the canopy does bring is in winter, I must have my pond covered with a leaf net or it gets really clogged. This is a small price to pay for everything the shade does.
What I will change
Contacting a professional
I started to dig my pond on my own. I planned my pond on my own with rather little knowledge of how these things really work. While digging, we realized that bringing in a professional water feature constructor would be a much better idea. I believe that’s one of the reasons my pond looks like water garden instead of a hole in the ground. Next time, I will bring in a contractor from the start.
I originally designed the pond to be aesthetically pleasing. I wanted it to look like a natural stream with the water flowing in from a waterfall and then out down another channel. It really does have that appearance. But this has also caused some problems for me. The idea behind the bog system is to have it be water storage area. It’s supposed to hold an extra 300 gallons of water and make sure the pump is always submerged. It also provides a shallow bog area to grow plants like rushes, cattails, and others. The main purpose of these plants is to be a nutrient sponge. However, these plants need full sun which my bog doesn’t get. My bog is also not large enough to have a lot of these plants. Next time, I will build a larger bog much closer to the pond and shorten the stream or completely forgo it.
Changes to the upper stream
I really like the setup I have with the large waterfall, but I think with the next pond I want to elongate the upper stream and make the first pool much larger. This will also give me more landscaping options, and I would like to put a path and a bridge over the upper stream. A larger pond will also allow more salamanders and frogs to live in my pond. These animals eat insect larvae and are also an indicator of water quality.
Right now I only have about 3 species of pond plants. I would like to add more, but there just isn’t the room or the sunlight. More plants will make the water cleaner and out-compete with the algae. Plus, I love the look of floating plants. The way I have the body of the pond set up now, floating plants just don’t work well. And I would also love some lilies, but again not enough sun. I would like to plan my pond so that some parts will get enough sun for lilies. This will also mean having a larger surface area.