This brief article is an important one and should be read by anyone who’s putting a pond aerator into a large pond during the summer season. It’s in response to a fellow who called about a problem of losing fish after putting an aerator in his pond during some extremely hot weather.
This is an interesting and a bit of a trickly situation because good aeration is a very powerful tool for protecting fish during hot conditions, there’s no question about that. But at the same time, anytime you introduce something new into a pond’s environment, certain things can happen that may not always be desirable.
In the case of large ponds, and particularly those that have some age on them, it’s not uncommon to find some muck or sludge build up on the bottom. Some of this can be very nutrient rich and many times it’s made up of decomposing or rotting organic material. Leaves or dead plant matter are often the culprits.
During this decomposition process gasses can be created, and they may lie trapped in this sludge until something comes along and disturbs it. Nature can do this all on it’s own by creating an inversion in the pond, where the bottom and top sort of switch. This can be a very dangerous time for fish because it really messes things up in the pond. Dissolved oxygen levels can drop, toxic gasses can be released, and basically all of this is just not a good event in the life of a fish.
Aerators can circulate a lot of good stuff in a pond, but if a partiuclar body of water has a lot of muck, an aerator’s action may also disturb this and most likely, this is what has happened to the pond owner noted above. That, and the introduction of the system was during very high termperatures which also place a special burden on a pond as well.
So, here’s the catch 22 of sorts. You need good aeration going during the hottest times of the year, just to help keep dissolved oxygen levels up in the water. Without it you will likely see fish suffer and many can die. But when you put it in, and if the pond has some muck on the bottom, you risk disturbing all of that, and losing fish too.
So here’s the best way that I know of to work around this situation.
Limiting The Initial Running Time
The first recommendation is to gradually introduce the aerator and the time that it runs in the pond. Our eventual goal is to have it run 24/7 for the best results, but it’s not always a good idea to just put the system in, turn it on, and let it go. This is often possible if very fresh, clean, and newly created ponds, but not older ones. No, in fact, we want to start the aeration introduction very slowly, meaning run it about 20 to 30 minutes the first day, a little longer the second day, and so forth until we get up to full operation in 2 to 3 weeks of time.
Anytime you see problems develop, such as a heavy clouding or discoloration of the water, or fish suffering, then back off on the run time and see if that settles things down. Slow and steady wins this game so don’t get in any rush at this point.
Work Your Way From Shallow To Deep
Another very important thing you can do is to avoid putting the diffuser(s) in the deepest part of the pond right off the bat. When diffusers are set deep, or as deep as you can go, you’ll effectively aerate the entire pond. This is the normal position in a well established aerator set up, and in particular the placement I suggest during the summer months. However, when you’re introducing aeration, particularly when you might suspect problems as we talked about above, it’s often best to begin aerating in shallower water. Start at about half the depth or less, moving the diffuser towards an end or edge of the pond and run it there for as long as you may need to during the summer season.
As conditions improve, meaning temperatures moderate and go down a bit, you can begin to move the diffuser into a bit deeper water and gradually position it at the deepest point. You can leave it there as long as the weather stays warm enough and come the following spring you should be able to operate at depth whenever you need to.
This repositioning of the diffuser is useful too in the winter months should you decide to operate the aerator then, and many people do. Simply move the diffuser to a more shallow position again and they’ll usually help to keep an area ice-free during the colder weather.
Ultimately having an aerator in your pond will greatly improve the health and conditions in the water for fish and the biological processes that help to keep a pond cleaner. It’s literally one of the best things you can add to your pond to help. And introducing the system as we discussed above should help you avoid some of the common issues that come up when folks try to introduce pond aeration during some of the more challenging times of the year.