Essential Tips for Every Minnesotan Water Gardener to Achieve Clear Pond Water
You may have just finished a long weekend of pond cleaning, trying to work around your fish and getting all the muck out of the bottom of your pond, or maybe you had a professional do it for you. After a few days or weeks, it happens again: a frustrating growth of algae. Maybe the water never cleared and has been cloudy ever since.
The charm of a low-maintenance pond—where elegant fish smoothly glide underneath lily pads and shimmering water—is something we all want. Understanding and managing water quality is important for any backyard pond, for a healthy system as well as for your enjoyment. The cloudy water, algae blooms, and unusual fish behavior could indicate underlying issues that will take the enjoyment out of your pond until they’re solved. With the right knowledge and techniques, you can easily tackle these common pond problems. Here are 10 key tips to help keep your pond water clear and in top shape all year!
1. Understand Algae
Algae, in and of itself, isn’t a bad thing. Algae is found across the entire world and is responsible for producing the majority of our breathable oxygen. Algae is a living organism that is vital to the stability of every ecosystem. When you see algae in your pond, it’s not time to be concerned. The concern is over algae blooms that overpopulate and take over the system. The goal is a balanced ecosystem, not an algae-free system.
2. Monitor Your Fun and Functional Fish Population
Fish are more than just pets, playing an integral role in every natural ecosystem. They help control algae by grazing on it, they produce nutrient-rich fertilizer for your pond plants through they waste, and stir up the bottom of your pond during their feeding which helps circulate debris through your system.
However, keep an eye out on your fish population. If you have more than 10 inches of fish per 100 gallons of water, your pond could be overpopulated, leading to excessive fish waste and water imbalance. It might be necessary to rehome some fish to maintain a healthy ecosystem. Oftentimes, you can easily rehome fish with other pond enthusiasts, pond retailers, and pond contractors. Many in local online communities and Facebook groups would be more than willing to take extra fish off your hands.
3. Feed Your Fish Properly
Overfeeding is a common mistake that can degrade water quality, as uneaten food sits and decays in the pond. It’s a good habit not to feed your fish than once a day, and only as much as they can consume in 2 to 3 minutes. Choose a high-quality, floating fish food, which is easier to clean out if uneaten. Don’t worry about your fish going hungry. They are happily living off all the many plants, algae, and other nutrients in your pond ecosystem.
4. Balance Plant Life
Plants are essential to your pond’s ecosystem, not just for their beauty but also for their functional role. As they begin to grow, they perform a filtering role and absorb nutrients from the water, out-competing algae for these resources and effectively starving the unwanted blooms. During peak summer season, aim for about 40% to 60% of your pond’s surface area to be covered or shaded by plants. As you add in plants, you’ll notice the water clarity improve as plants like water lilies and water lettuce, which also shade the water’s surface, thrive and reduce the presence of string algae and green water. However, don’t completely cover your pond. Plants pull in extra oxygen at night, which can deplete the oxygen levels in your pond for your fish if you have too many plants.
As your choosing pond plants, here are some great options to choose from:
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Creeping Jenny – often used as ground cover, Creeping Jenny is a great perennial option to soften up rock edges and as a filler plant. Best used in Zones 3-10.
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Water Lettuce – a well-known water plant among aquarium enthusiasts, Water Lettuce produces rosette shaped leaves that look like floating lettuce in your pond. This is a super easy plant to grow in your pond and easy to share with your pond friends. Hardy in Zones 9-11
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Waterlilies – one of the most well known and recognized water garden plants, waterlilies are a must-have in your pond. Their floating leaves are typically about 2”-6” around depending on the variety and grow up from the bottom of your pond on a shelf from either a growing bag or basket. You can find flower colors from any spectrum you want that will give you several beautiful blooms throughout the summer. There are two groups of waterlilies, hardy and tropical, be sure to choose the right one for your zone.
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Checkout this list of Minnesota friendly water plants at the bottom of our article on Creating and Effective “Bog” and Wetland Filter for more plant ideas!
5. Use the Correct Pump Size for Water Circulation
Circulating the pond’s entire volume at least once every hour is essential for maintaining water quality. It’s difficult to balance a pond ecosystem without proper flow and circulation. Make sure that your pump is free of debris to avoid flow restrictions and always choose a pump that matches the pond’s size requirements. Check it often to be sure that the pump isn’t getting clogged. When you are choosing a pond pump yourself, use resources like online pump selection guides to make an informed choice. Most pump suppliers will have selection guides for you to make the best choice.
If you’re trying to doublecheck the correct pump you need for your pond, use this: (plumbing length + 10) + number of 90 degree fittings + elevation = application head height.
6. Regularly Remove Debris
Use a pond skimmer or a net to remove surface debris before it sinks and decays. Mechanical skimmers installed into your pond will automatically remove floating debris, otherwise net by hand on a regular basis to keep from having a buildup on the bottom of your pond. Decaying organic matter, combined with fish waste, can spike ammonia levels, which are toxic to fish.
7. Provide for Adequate Filtration
Ensure your pond’s filter matches the size of your water feature. Oftentimes, issues with the quality of your pond water stems from inadequate filtration. Filtration is both mechanical and biological, using both filter mats and bioballs to house beneficial bacteria and other helpful organisms to combat water clarity issues. When you’re placing the filtration during pond construction or rehab, be sure to account for dead areas and ensure that the whole pond is being adequately filtered. Considering that most filters are rated for ideal conditions, it’s often better to choose a slightly larger filter to accommodate unexpected load increas
es. When in doubt, go up a size. And don’t forget that regular filter maintenance is also crucial to its effectiveness. A clogged filter is as much good as no filter, or worse because you remove the water flow.
8. Manage Water Temperature
During hot weather during the summer, it’s important to keep your pond cool as warm water holds less dissolved oxygen, which fish need to survive. If you have an uncovered pond liner or preformed pond, the black color absorbs a lot of heat from the sun. Covering up with rocks and gravel not only gives beneficial bacteria places to live, and naturalizes your pond for you and your fish, but also drastically reduces heat absorption in your pond. Adequate shade from aquatic plants can also help, as well as adding an aerator to provide immediate relief during heat waves.
9. Add Beneficial Bacteria
Talking about beneficial bacteria, don’t forget this microorganism when you’re troubleshooting your pond water. Living in the biological filter and within the rocks and gravel of the pond, beneficial bacteria play a vital role in keeping your water clear. Like aquatic plants, these bacteria consume excess nutrients and help break down organic matter. It’s essential for the health of your pond to establish these helpful microbes early in the spring. There are so many types of bacteria out there wanting to colonize your pond, getting help with the right kind gives the beneficial bacteria the opportunity they need to be the predominant organism.
To kickstart the bacteria population, consider adding a product like Aquascape Cold Water Beneficial Bacteria in the spring, which is formulated to thrive even in colder temperatures, as low as 35°F (2°C). This can significantly enhance the biological filtration capacity of your pond. To control more extreme situations in your pond, an IonGen system or Algaecide might be needed.
10. Patience is Key
It’s important to allow time for the growing plants, balanced fish populations, beneficial bacteria, adequate filtration, strategic use of rocks and gravel in your pond to acclimate and start their work. It doesn’t happen overnight. With a little patience, you’ll enjoy the rewards of a well-balanced, low-maintenance ecosystem in your pond.
Enjoying Your Pond
With these steps, you can create and maintain a pond ecosystem that requires minimal upkeep with clear water. Dive into better pond-keeping with these foundational elements, and you’ll find maintaining your water garden is a breeze, allowing you more time to relax and enjoy the tranquil beauty of your outdoor oasis.