Asked June 1, 2016, 11:04 AM EDT

We have a pond in our front yard, it measures approximately 20' in diameter and about 8' max depth in the center. There is a waterfall, and this year we installed an aeration system. Can you tell me if it is beneficial to order pond bacteria online, in order to help improve clarity? I have read some information that suggests the bacteria that is sold, is not the same as what would live in a pond. Any information would be appreciated.

Roscommon County Michigan

3 Responses

Hello and thank you for using eXtension for answers to your pond questions. Before I offer advice about your pond can you tell me more about it? Is this a fully artificial pond and if so how old is it. Is is a natural pond that you added a waterfall to? Are there other things in the pond such as plants and fish? what is the bottom or soil make up of your pond. do you mow your lawn right to the waters edge?
Adding bacteria to a pond because a catalog declares it is helpful isn't always the answer to water clarity issues. Knowing the ecosystem you are re-creating is.

Warm regards,

Hi Beth, thanks for your response. Our pond is man made, and 13 years old. I do completely drain and fill it every couple of years. The water appears to be cloudy due to plankton algea, with minor concentrations of string algae. We introduced hybrid bluegills into the pond late last summer, but they all died over the winter. A new group of 25 were introduced just a couple days ago. In addition to the bluegills, there are minnows and 4-5 turtles.

Our lawn consists of native grass and I do not fertilize it, so no runoff from that. Also, the grass does not grow right to the edge of the pond, so I do not run the mower very close to it. The pond has a rubber liner covered with sand and pebbles. We have two water lilies, some reeds that look similar to Barred Horse Tail, another plant that looks quite similar to, but not exactly like, Variegated Sweetflag & another plant that I have no idea about. I hope this helps to give you a better understanding of the conditions.

Thanks for your quick response. I can see a couple of things here that may be of issue. Draining and refilling your pond with fresh water effectively sterilizes the system putting your ecosystem back to zero. this can cause you several more years in creating a balanced ecosystem in your pond.
Algae and other things are natural in every water system so water clarity is then what you may perceive it to be. If you want fountain or swimming pool clarity then you can't have plants and fish that will live and thrive in your pond. If you want to manage for fish then you will have to tolerate water that is somewhat more cloudy. That being said, you also don't have to live with pea soup green either. Bluegill are plant feeders they need aquatic vegetation to both hide in an eat. Your pond should have a balance of aquatic plants and a good filtration system together. This will help to keep your pond clean.
It will experience times of "turnover" when there is an algae bloom typically in the spring and again in the fall. if you have a good pump and filter with a waterfall then oxygen in the water should not be a problem. These need to operate year around and you need to make sure in the winter that you keep a hole in the ice for gas exchange. You will have to artificially feed your fish until a plant community is established enough to support your school. Don't over feed them this will just feed the algae. They do not need to be fed in the winter.
Adding bacterial is optional and often not necessary. Keep your pump and aerators off of the bottom as these can influence stratification in the water making your pond too warm or too cold.
Here is a book in pdf that can help you manage your pond better. and this Q & A fact sheet
Maintaining d diverse plant system in your pond can help with both water clarity and provide for your fish.
I hope this helps.
Warm regards,