Choose the BEST Aeration System for your Pond!
One of the best actions you can take for your pond is to install a pond aerator. This one, simple improvement will help the pond ecosystem to thrive. The pond ecosystem relies on beneficial, oxygen loving bacteria to remove nutrients and break down organic waste in the water. Without aeration, these bacteria are limited by the amount of oxygen available in the water column. Further, as the surface of a pond warms, cooler water settles to the bottom creating a layer of poorly oxygenated water that can extend from a few feet below the surface to the pond bottom. The upper 18-24” of water remain will oxygenated, but the rest of the pond has limited oxygen. This also significantly reduces the oxygenated water volume available for fish and other aquatic life.
Guide to Pond Aerators
There are a variety of pond aerators available. Let’s avoid the confusion of selecting the proper type of aerator by reviewing the most common aeration systems available.
The best pond aerator is one that aerates the entire pond from top to bottom. For ponds deeper than 3 to 4 feet, that is a bottom aeration system. A bottom pond aerator uses an air compressor placed on shore (and even some distance away from the pond shore) to force air to diffusers that are placed on the pond bottom. This adds oxygen to the pond water in two ways. One, as the fine air bubbles rise through the water column, some of the oxygen is absorbed into the water. The second, and much more effective way that oxygenation occurs is by lifting poorly oxygenated water from the pond bottom to the surface. This happens as a result of the rising column of fine air bubbles creating a lifting current in the pond. Most bottom aeration diffusers generate 5,000 gallons a MINUTE or more of water flow from the bottom of the pond to the top. Once the water is at the top, it is exposed to the atmosphere and absorbs oxygen to it’s saturation point.
In ponds and lakes deeper than 6 feet, a single aeration diffuser can aerate a significant portion of the pond. As a general rule of thumb, the deeper the water body, the more effective a single air diffuser location will be because the lifting current created by the rising air is larger and circulates more water.
In ponds shallower than 6 feet, The best approach is to distribute a number of smaller aeration diffusers throughout the pond to create more points of circulation.
One often-overlooked benefit of bottom aeration systems is the low operation cost. Many bottom aeration systems can be operated for less than a dollar day.
Floating fountains are also effective in aeration for shallow ponds and lakes. Floating fountains are broken into two categories – those with decorative patterns and those whose primary function is aeration.
The decorative pattern floating fountains range in size from ¼ horsepower fountains that generate spray patterns less than 4 feet high to giants with up to 25 horsepower motors that launch water 50 feet into the air. Because the floating fountains typically draw water from within 4 feet of the water surface they are very effective at surface aeration but do little to add oxygen to the deeper areas of the water body.
The high oxygen transfer floating aerators function similarly but move a greater volume of water and essentially “churn” the water with air to effectively aerate shallow ponds. Again, these systems draw from relatively shallow water so oxygen levels at depth don’t benefit.
Excellent Aeration with a Decorative Fountain
A growing number of ponds and lakes feature both a bottom aeration system for maximum aeration and a decorative floating fountain. The bottom aeration system is installed to maximize oxygenation throughout the water body at a low operating cost. The floating fountain can be added as a decorative component that is operated by a timer or photocell to reduce the operating costs, which can be significant for larger fountains. Floating fountains can also be very effective at minimizing duckweed and watermeal growth on the surface. These plants require calm surface conditions for growth so the surface agitation caused by the fountain spray limits the plant’s ability to grow.
What if there is no electricity at my pond or lake?
There are several options available!
Solar pond aerators
Solar pond aeration uses the same bottom aeration concept to maximize aeration throughout the water column.
There are 2 types of solar aerators. Daytime operating solar aerators do not have battery banks and storage chargers. Because of this, they only operate when sunlight is on the solar panels. The benefits are smaller solar panels and less initial expense for the system. Of course, the main drawback is that aeration doesn’t occur overnight which can be one of the most important time periods for aeration since oxygen demand in a pond is often at its highest in non-daylight hours.
Solar pond aerators with larger solar panels and battery storage solve this problem with continuous operation.
Windmill pond aerators use a simple, wind operated compressor to drive air to bottom diffusers to circulate the pond. The obvious drawback to windmill aeration systems is the lack of aeration on calm days. Unless your pond is located in an area with regular, consistent wind speeds of 8mph or higher, a solar pond aerator is a more effective choice.