Prevent Algae from taking over my Pond

You are not alone if you want to say “I’m struggling with the same kind of algae taking over my pond. What’s going on?” The answer is biology. We pond owners have inadvertently stumbled across one of natures microscopic battle grounds.

There is a microscopic battle that happens in our water features occurring on a daily basis. Plants, including algae, beneficial bacteria, and other aquatic species are competing for the same food and light in your pond. Problems occur when one species dominates the ecosystem, creating a monoculture. When this happens, the dominate species will suffocate everything else. For example, we generally don’t see filamentous algae and green water problems at the same time because those are two different types of algae fighting. Your pond may have green water or it may have string algae mats clogging up everything, but not both.

Let’s see what Jeff, Master CAC pond builder has to say about preventing algae from taking over his ponds:

The first step to a clean pond water or koi pond is to check the water source. (Water from a well can have surprising amounts of certain nutrients!) Jeff says check:

nitrates, phosphates, total nitrogen, pH, potassium, iron, and overall hardness in the water.

Regardless of what the well water test shows, you still have to deal with a green pond. Knowing what is in your water simple helps you deal with it faster. For example, high levels of phosphates can be treated with phosphate binder packets if the pond is large. (We don’t recommend this treatment for small, container ponds though.) Large amounts of nitrates can be handled by cleaning debris out and adding extra bacteria to eat the nutrients.

The second step is to identify which species of pond algae is dominant.

Does your pond algae look stringy? This is filamentous algae.

Do you have green pond water that almost looks neon green? This is planktonic algae– tiny, tiny plants that color the water green, blue-green, or brownish.

Do you have what looks like algae growing from the bottom of the pond up? You may have chara, a plant that looks similar to algae but is very brittle and stinky.

Thick mats of string algae or meadows of chara growing on the bottom of the pond can be knocked down by hand pulling or spot treating with algicide or herbicide (chara). After initially knocking down the population of aglae or plants, the extra food in the water (nutrients) needs to be removed in order to prevent another overgrowth.

The third step is to decide on an appropriate pond treatment plan:

As odd as it may sound, you can fight algae with algae! If you have green pond water (planktonic algae), adding some green filamentous algae to your pond wetland will help! This string algae will act as a tertiary component of the filter and it will consume a lot of extra nitrates and phosphates from the water. Adding a bit of filamentous algae can help balance your pond life by competing with the other algae.

As we mentioned above, there is a war between plants and bacteria for available nutrition in your pond. Support the team you want to win! If you don’t want to fight algae with algae, there are other methods such as algicides, herbicides, or beneficial bacteria.

📃📃📃 Here is the daily backyard pond treatment “To-do list” to preventing green water:📃📃📃

To boost good bacteria which leads to clear water in your backyard pond, treat your pond every morning. Also use SAB every evening. If your pond water looks like pea soup, it will stay like that for around 3 weeks then magically transform to clear water overnight. (You will think we are stupid and consider giving up on daily bacteria treatments but this has worked multiple times for us.)

*Do: Every morning x 3 weeks: Add the correct amount of beneficial bacteria. Use cold water bacteria from 32-50F. Then switch to regular bacteria for water over 50F.

*Do: Every evening x 3 weeks: Add correct amount of SAB Stream and Pond Cleaner which helps to break down organic debris and maintain a balance in the water while the phosphate binder prevents water quality issues. 

*Do: Once a week to once a month, clean your skimmer of leaves, grass clippings, or seeds that get trapped.

After week three, you can slow bacteria treatments down to weekly doses or spot treat string algae mats as needed. By now, there should be a healthy community of bacteria competing with algae in your pond.

A special note: Leaks can undo all this hard work by putting fresh nutrients in constantly and diluting the bacteria. Leak checking sounds hard but it really is a simple process. Give us a call if you need some assistance. Enjoy your koi pond or waterfall this year!

Enjoy a clear pond without green water
Quick Contact Form Call Us