When pond water stagnates because of stratification, a sulfur odor results as gas from microbes in the base of the pond flows to the atmosphere. Stratification occurs when no motion is in the water. The top of the river receives oxygen in the water surface, however, the pond’s bottom layers become depleted of oxygen since the germs work on decaying matter that sinks to the river’s bottom. When the weather changes, the stratified layers are disturbed, along with the gas and also oxygen-depleted water climb to the peak of the pond, causing a sulfur, or rotten egg, odor and suffocating fish. Adding movement to pond water to prevent stratification keeps the pond odor-free.
Install air diffusers at the bottom of the pond. They’ll circulate the water throughout the thickness of the pond. The number of diffusers needed varies based on the pond’s size and thickness. As an instance, small, shallow ponds need less extra aeration than little, deep ponds since they have a larger surface area-to-water volume ratio. Use air diffusers that produce a large number of little bubbles to raise the amount of oxygen.
Add a water feature, such as a fountain or a waterfall. It helps agitate the water and keep it going. A water feature is not as effective than air diffusers; therefore it needs to be used in conjunction with air diffusers or in a shallow pond where the fountain’s nest’s water will reach the pond bottom. Otherwise, the pond still will be stratified; it just will have extra oxygen in its surface layer of water.
Examine the pond’s filter media daily after installing air diffusers or a water feature. The increased water agitation from diffusers or a water feature stirs up debris at the pond’s bottom so it can be filtered out. Until the waste material is completely filtered out, extra matter will be from the filters; so they need to be rinsed out more frequently than usual to remain operating effectively. When you remove the filter media and it isn’t dirty, then you can go back to rinsing the media weekly.