Lake Aeration TT36
Published on May 12, 2014

Lake Aeration - Tech Talk 36

It takes a lot more than bubbles to do it right ...

It takes know-how and a properly-sized Great Lakes® aeration/destratification system.

Most lakes cover vast areas and contain millions of gallons of water with a biological oxygen demand (BOD) of 10 mg/L or less. So a few random air bubbles rising from the bottom just aren't enough to satisfy a lake's need for oxygen. But, use that same small volume of air to induce a significant rising current, and you have an extremely efficient lake aerator!

Pentair Aquatic Eco-Systems synergistic airlift diffusers are designed to lift and circulate huge volumes of water, bringing life-giving oxygen from the surface to the bottom. These unique air diffusers were specifically engineered to cause an upwelling current without turbulence or bottom erosion.

The 4-sq.ft. diffuser assembly creates a vertical current using the rising force of air, moving low oxygen water up from the bottom and eliminating stratification. Hundreds of man-hours have gone into the development of this technique, including underwater dye-flow studies and destratification experiments.

The system is simple, safe and virtually maintenance free. It is the most effective lake aerator made! As little as 3/4 horsepower can be used to properly aerate a eutrophic 10-acre lake!

Technically Speaking

  • When oxygen levels are low, you can expect transfer performance of more than 10 pounds of dissolved oxygen per horsepower per hour! (Pumps, fountains and "air bubblers" are typically fewer than 2 pounds per horsepower per hour).
  • Bubbles expand and spread out as they rise. The column of water entrained within the bubbles from a synergistic diffuser rises at about a foot per second, moving 2,000 gpm from the area above the diffuser (a drilled pipe diffuser with the same air volume would move only about 200 gpm).
  • The surface boil–created by the kinetic energy of the rising water–rises approximately two inches above the surrounding water level. From there, the water rushes outward until its energy has dissipated, sometimes traveling more than 100 feet, depending upon temperature, surface tension and wind.
  • The lake surface tension is ruptured in the boil area. Supersaturated gases, including carbon dioxide and hydrogen sulfide, escape from the bottom water, and oxygen is absorbed.
  • There's no danger to swimmers, boaters or aquatic life—even a marking buoy is unnecessary. And, like hundreds of others, you'll enjoy watching the surface "spring" boils. There is no electricity in the water.
  • It's best to install the system prior to stratification. If the volume of anaerobic bottom water is greater than 1/6 of the lake's total volume, contact us for start-up instructions.
  • Every lake is different. A Pentair AES aeration specialist will be happy to assist with equipment selection and system design. We'll need to know the lake's shape, size, depths, history, bottom type, water source, flow, etc. 

Below are before and after pictures of our pond. Your recommendations worked! It took about 4–5 weeks for the pond to completely clear up, but we are very pleased with the results and appreciate all your help. Our bog garden was only mildly impacted by the Sonar product. All the ponds beyond ours are covered in scum and duckweed while ours is clear and beautiful. I should have contacted you guys years ago. Appreciate your advice. I would be glad to recommend your company and products to anyone who asks.

- Roland Fortner

Lake Aeration