Aeration is the process of adding oxygen to water, which is essential for keeping a pond or lake healthy and clean. There are two main types of aeration: surface aeration and sub-surface aeration. In this article, we will discuss the differences between these two types of aeration, their use cases, pros and cons, and suggest the best use case for each type of aeration.
Surface aeration is the process of adding oxygen to the top layer of the pond or lake. It is achieved by physically breaking apart the water, creating more surface area for gas exchange. This can actively add large amounts of localized oxygen to the water, which helps control top-level algae and weeds. However, surface aeration does not aerate down to the bottom of the pond where oxygen is needed most. This method is typically employed in recreational an/or commercial aquaculture applications wherein large amounts of oxygen may be needed to solve abnormally high BOD’s (biological oxygen demands) that may be imposed on the water. Typically, water at the bottom of ponds is colder and contains less oxygen, which is called thermal stratification. If a pond is stratified, fish will hang around the top layers of a pond where there is more oxygen.
Benefits of Surface Aeration
- Helps control top-level algae and weeds
- Adds large amounts of oxygen to the water
- Can aid in solving high oxygen demands such as oxygen depletions
- Generally easy to install and maintain
- Lower up-front cost
Points of Consideration With Surface Aeration
- Ineffective solution to keeping and maintaining your pond in a healthy and balanced condition
- Does not aerate down to the bottom of the pond where oxygen is needed most
- Limited by power location as power cords can only be run so far
- Not suitable for ponds or lakes that exceed 5′ to 6′ in depth
Sub-surface aeration is the process of adding oxygen to the bottom of the pond or lake. It is achieved by compressing oxygen and pumping it into the water through diffusers placed on the bottom of the pond or lake. This type of aeration is generally desirable when a pond or lake exceeds 4’ or more in depth. Sub-surface aeration promotes complete mixing and destratification of the water, which helps reduce muck and sludge from settling on the bottom.
Benefits of Sub-surface Aeration
- More effective and efficient than surface aeration
- Promotes complete mixing and destratification of the water
- Reduces muck and sludge from settling on the bottom
- Suitable for ponds or lakes that exceed 4′ in depth
- Air lines can be run up to one mile from the power source
- No electricity runs through the water, making it safe for people or pets to enter the water
Points of Consideration With Sub-surface Aeration
- Generally they are more expensive than surface aeration, depending on the application
- Can be a little more difficult to install than surface systems
- Requires a power source to operate
Best Use Case for Each Type of Aeration
- Surface aeration is best when a body of water needs frequent oxygen for emergency needs and is less than 3.5-4’ in depth.
- It is also suitable for ponds or lakes that have limited power source locations and are not used for swimming or other activities.
- Sub-surface aeration is best when a pond or lake exceeds 4’ to 5’ in depth and needs complete mixing and destratification of the water. It is also suitable for ponds or lakes that are used for swimming or other activities as no electricity runs through the water.
- Sub-surface aerations is also best when pond owners plan to strive for a quality and productive fishing lake and also practice consistent management practices, both requiring consistent and dependable levels of oxygen.
Both surface and sub-surface aeration are essential for keeping a pond or lake healthy and clean. However, the best type of aeration depends on the depth of the pond or lake, the use case, and the budget. Surface aeration is cost-effective and easy to install, but it is an ineffective solution to keeping your pond healthy. Sub-surface aeration is generally more expensive and difficult to install, but it is more effective and promotes complete mixing and destratification of the water. Therefore, it is important to consider the pros and cons of each type of aeration and choose the best one for your pond or lake.