Q: What is causing the bad odor coming from my pond?
Keith – Cedar Bluff, AL
A: There’s nothing worse than that musty, rotten egg, sulfur-type smell that’s pungent enough to ruin spring strolls by the pond. What causes it and what can you do about it?
Those odors are common in ponds that aren’t aerated, particularly during certain times of year. In the summer and winter, non-aerated ponds stratify into layers of water with distinct temperature differences. This locks the bottom layer away for months.
While the water layer is trapped down there, the oxygen is used up quickly. It goes from an aerobic environment to an anaerobic environment – which is perfect for slow-moving anaerobic bacteria that use enzymes to ferment and digest the decaying muck on the bottom. Those microorganisms ultimately produce waste products, including carbon dioxide and hydrogen sulfide, which is that lovely rotten egg smell.
In the spring and during strong weather events, the water column turns over; the anaerobic layers on the bottom rise to the top, bringing with it all those foul-smelling odors. That’s likely what you’re experiencing with your pond, which could be made worse by melting ice releasing all those gases at once.
So what can you do? At this point, first test your pH and water quality, as pond turn-overs could cause pH shifts, dissolved oxygen crashes and algae blooms that could harm or kill your fish (which could add to the odor problem …).
If the water temperatures in your pond are 50 degrees Fahrenheit or above, add some Pond Logic® MuckAway™ and Pond Logic® PondClear™. The beneficial bacteria in the products will help break down the decaying muck on the pond bottom as well as clearing up suspended particles in the water column.
As soon as you can, install an aeration system and crank it on. Our Airmax® Aeration System product line includes aerators suited for any size pond – from shallow water bodies to ponds up to 6 acres. They each include diffusers, a compressor, cabinet, airline and free mapping service that takes the guesswork out of diffuser placement.
Finally, cut and rake out dead and decaying organic material with a weed remover tool. The more you can eradicate, the better it’ll be for your pond’s water quality – and stink factor.
Pond Talk: How do you prevent or manage the odor coming from your pond?