I have a small pond, about 1/4 acre, 12-15 feet deep, and have a bad algae problem. No ag or fertilizer run off since owned property 1975. We did swim in the pond until about 15 years ago. I spend a ton of money every year having pond people try to control algae with chemicals, I added a bottom aerator two years ago. There are trees on the east and west side and I’m wondering if there’s an issue with air flow? I was going to add a surface aerator but thought before I spent another 3-4k I’d reach out to MSU and see if you had a recommendation. Thank you so much! jan godek
Washtenaw County Michigan
Hello and thank you for using MSU Extension eXtension for your pond algae question. two things, if your aerator is on the bottom of the pond you are raising nutrients from there to feed your algae. Raise your aerator up at least two feet from the bottom of the pond this will stop stirring up the silt from there. The shade from the trees will actually help by blocking the sunlight from the water thus reducing plant and algae growth.
Adding chemicals creates a death and decay cycle increasing nutrient loading in the pond. switch to a dye. pond plants are critical for insect and animal life for food, shelter and nesting sites. encourage other natural aquatic vegetation to grow in your pond. use only native plants. go to https://www.mishorelinepartnership.org/plants-for-inland-lakes.html to find a great plant list for lakes and ponds.. you may not need a second aerator. Give your pond a few years to recover and re-stabilize. Note that it is normal for bodies of water, lakes and ponds to experience spring and fall turnover which results in an temporary algal bloom. this typically clears up by summer or winter. here is an article abotu that https://www.canr.msu.edu/news/the_thermocline_a_summer_phenomenon_in_michigan_inland_lakes here is another article about natural ponds https://www.canr.msu.edu/news/preserve_your_natural_backyard_pond