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When looking for a solution to managing water quality, or simply for aesthetic enhancement, there are three basic types of pond and lake aerators to consider; surface spray aerators, air diffused systems and horizontal aspirators or mixers. Each type has unique differences and efficiencies that can be used in many different ways to achieve maximum benefit.
Selecting an Aeration System
The size, shape and depth of a pond should dictate the type of aeration system, or combination of systems used. Keep in mind when water quality management is an objective, recommended sizing is 2-hp per surface acre.
- Surface Spray (Floating) Systems: Ponds less than 15-ft. deep, or wherever fountain spray aesthetics are desired.Diffused Aeration Systems: Ponds 15-ft. and greater in depth, and when no surface spray is desired. (Note: Efficiency is lost when used in ponds less than 15-ft., but can be remedied with additional diffuser manifolds placed throughout the pond. These systems are not recommended for ponds less than 8-ft.)
- Mixers and Aspirators: In ponds less than 9-ft. deep where lateral movement is dictated, or no surface spray is desired.
Surface spray aerators in ponds or lakes less than 15 feet, lift bottom water to the surface and spread it out over the surface to aerate and create convection currents. The wave action of the spray breaks up algae mats and discourages mosquito breeding. This geyser-type was designed for ornamental interest. These units can be powered by 1 to 5 hp motors, which allow spray heights from 11 to 23 feet and spray diameters from 5 to 8 ft.
Photos: Otterbine Barebo, Inc.
Electrical Requirements
To operate the systems efficiently and without nuisance tripping it is necessary to know if sufficient power is available, how close it is to the source, and if there are other electrical requirements that may be using the same source, i.e., irrigation, lighting, etc. It’s also important to follow local and national electrical codes during installation, which will often require burying/trenching wire in conduit from the power source to the aerators power control center, and from the PCC out to the ponds edge.
Having operational electricity is necessary before flotation and start-up of any aeration system, for security and mechanical considerations, and may become a scheduling consideration that could need attention. A certified electrician may also be required during installation.
An air diffusion system creates strong currents and oxygenation without a spray pattern. These fine-bubble diffused industrial aerators have piston compressors that allow them to operate at depths up to 40 feet.
Photo: Otterbine Barebo, Inc.
System Installation
There are two ways of securing most units into position, anchoring (to the pond bottom), and mooring (to the pond edges, either above or beneath the surface.) Methods of securing and quality of materials used can affect security, ease of service, and safety and should be included in the planning. Tools and materials required can include: a shovel (to bury/trench cable,) conduit, stainless steel cable or nylon rope, cinder blocks and a boat (when anchoring,) and rebar or duckbill anchors (when mooring.) Diffused air systems do not require anchoring or mooring, but a boat is often required during installation.
Intensive landscaping around the pond—retaining walls, waterfalls, and planting beds—could affect installation and service or maintenance access. Further coordination may be needed between the aeration installer and landscape and/or irrigation contractor in these instances.
The front aerator, called a fractional aerator, is a floating aerator ideal for ponds less than an acre in size. It can operate in as little as 13” of water and uses only a 1/4 or 1/2 hp motor. The float construction is roto-molded from a black polyethylene material and is filled with a closed-cell polyurethane foam. The float is capable of providing full floatation if the shell is punctured or cracked. A debris screen of 1/4” nylon mesh surrounds the intake of the aerator.
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