When Should I Aerate My Pond?

The question today is when should I aerate my pond?

In most cases, 24 7 operation is the best when it comes to aerating your pond.

There’s a couple of reasons for this. We want to maintain good dissolved oxygen levels in the water at all times.

The better we do this, the better and more consistently we’ll see the biological processes supported. This helps keep a pond cleaner.

If you have odors that will help reduce those. If you have unwanted growth like algae, it may help with that kind of thing as well. Overall, it just helps the natural balancing and cleaning processes of the pond work better, the higher or more adequate you have for dissolved oxygen levels.

Maintaining a good DO (dissolved oxygen) level also helps to protect fish during times of stress. This would include periods in the summer of very high heat and also sometimes through winter conditions where long term ice coverage could lead to winter fish kills.

There’s a few caveats to this though.

24 7 is best in most cases, but in a few instances we want to consider making some changes or adaptions to how we run the aerator.

In very hot conditions, typically you would have temperatures of 90 to 100 degrees, atmospherically speaking. Water temperatures might be 85 to 90 plus.

If you have a shallow pond in very hot conditions with fish, you may want to run the aerator only during the nighttime period. This helps to limit the mixing of the pond water and to attempt to keep the pond a bit cooler during these very high temperature extremes.

Certainly fish need good oxygen levels during these times, but they also have to have a reasonable temperature range or they could become heat stressed.   So you limit your aerating to the cooler time of the 24 hour period. This really involves mostly subsurface aeration as is pictured here.

A surface fountain or an aerating fountain could probably be run full time if you wanted to, but subsurface will mix the top and bottom waters too much in shallow ponds.  Note, this is mainly during very hot conditions and in ponds with fish, so you want to be careful in those settings.

Also, some people do use aerators like the subsurface systems in wintertime.

Typically, for most people, they will use them spring, summer, and fall. And if fish aren’t involved in the equation, if it’s just a water quality issue you’re working with, then you could shut the aerator down over the winter months.

But for winter usage you are only attempting to keep a spot of ice open. Wisconsin DNR suggests around 3% of the surface area should be kept open for proper gas and oxygen exchange during the winter months. And this is used strictly and solely to protect fish.

In summery, if you’re going to run an aerator, you want to try to run them 24 hours a day, seven days a week, for the best results.  Maintaining consistent and abundant oxygen levels in the pond will help to keep the pond cleaner and healthier overall.  Algae and other unwanted plants will often be hindered, while fish populations typically thrive in well oxygenated waters.