Ponds are organic systems that beautify the home landscape. You can keep fish in your pond or just plants, but either way you must have a chemical and biological balance in the water to prevent it from getting cloudy. Cloudy water can indicate poor pH, a lack or excess of bacteria, algae bloom, debris and high ammonia or nitrate levels. One of the reasons that might cause cloudy water is lack of oxygen which can be a dangerous situation if you keep koi. It is best to test your water before embarking on a treatment program for the cloudy water.
Dip a water test strip into your pond. Compare it with the test guide that came with the strips. The colours on the strip will change in response to different chemical and pH levels in the water. The test guide will tell you if the levels of chlorine, nitrate and ammonia are satisfactory. It will also tell you the pH of the pond. Koi ponds need a pH of 6.8 to 7.5.
Install a biological filter in your pond. A regular filter doesn't grow beneficial bacteria. The bio-filter will grow bacteria that will help restore balance to the pond water. The beneficial bacteria will break down any excess organic material.
Remove floating debris that will cloud your water. Any overhead plants can drop leaves or visiting animals may leave food or other material in the pond. Skim it clean.
Install water plants. The plants increase the oxygen and will use any minute floating organics in their growth. Floating plants will produce shade which will deter the growth of algae. They filter the water through their roots and clean the pond.
Make sure your water pump is working. Pumps and aerators are important to increase the oxygen in the water. This promotes good aerobic bacteria and the formation of "patina" which is the layer on the bottom of the pond that contains helpful organic material.