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How To Keep Your Water Feature Algae Free

There’s no question that adding a backyard water feature to your outdoor space can provide multiple dimensions of interest to your outdoor living area. Whether you decide to install a fountain, contained pond, or are just looking to maintain a simple pool or birdbath, a water feature can bring relaxation, wildlife, and an individualized design touch to your backyard. However, all water features also run the risk of experiencing algae build up.

Though many water features can be straightforward to install, they are not hands off once placed into your space. Water features require regular upkeep to ensure they continue to look their best. One common issue that must be avoided with regular housekeeping is algae buildup. Left unmanaged, algae can quickly overtake a fountain, pond, or even pool. Left for a long period of time, this can cause damage.

If you’ve newly installed a water feature in your outdoor living space, here’s some background on why algae forms, and how to manage, prevent, and get rid of it altogether.

Why does algae form?

Understanding why algae tends to grow in outdoor water features plays a big role in preventing its occurrence. Algae is an organic plant matter that grows and thrives in aquatic settings. Though most of us are familiar with the pond scrum and unfortunate blooms seen in our inground pools, algae encompasses a vast variety of species.

In the case of backyard water features, a few key elements cause algae blooms to take hold. A perfect recipe for an algae bloom will often include the following elements:

Warm Weather

Like most plantlife, those in warmer climates are likely to see algae blooms explode in late spring and summer months. Those in year-round warm weather climates may have issues with algae blooms any months of the year.


A recirculating fountain is full of algae.

Most plants thrive in sunny spaces, and algae is no exception. The more access the spores are given to photosynthesize, the faster and more solidly algae blooms will spread. Sunlight also warms the water, improving conditions for algae growth.

Poor Circulation

An effective way to prevent the growth of algae is to keep your water fixture well-aerated. Stagnant water allows algae particles to take hold and multiply quickly. Just as you would avoid still or standing water in your yard to prevent mosquito spread, the same can be said for preventing algae build up.

Low Free Chlorine

For those with backyard pools or spas, incorrect chlorine levels can contribute to the growth of organisms. Algae thrives in water with a higher pH, and those failing to routinely check their pools chemical balance can find themselves dealing with an unexpected bloom.

Nitrates and CO2

High nitrate and Co2 levels provide the perfect conditions for algae to thrive. As is the case with chlorine, failure to maintain the chemical composition of your water feature can result in unwanted, repeated algae growth.


Algae is often introduced to water features by way of common contaminants. Wind, rain, unclean swimsuits, and animals carrying algae spores are all incredibly common sources. When spores are introduced into favorable conditions, they will multiply quickly.


While many may envision algae as a problem affecting more naturalistic features such as ponds and birdbaths, any pool owner will tell of you of the dreaded algae bloom which can quickly turn an entire swimming pool green. Preventing this is contingent on a few basic maintenance steps:

Maintain Proper Pool Chemistry

Backyard pools contain chlorine for a reason! Proper levels of chlorine in an outdoor pool should be between 1.0 and 3.0 parts per million. Any lower than this and the pH of your pool may rise and create easy conditions for algae to multiply.

If you notice an algae bloom beginning, it can be treated by shocking your pool. Shocking a pool consists of treating your pool with a very high level of chlorine to kill the blooms. Afterwards, you should take care to thoroughly clean the water and lower the chlorine composition before swimming.

Regularly testing the chemical composition of your water will alert you when conditions are changing, and it’s time to make adjustments. Getting into the habit of checking and treating your pool water as necessary will help keep you ahead of the curve.


Those who are prone to algae build up in their pool may want to consider adding algaecides to their water. Many swimsafe algaecides are on the market, and can be highly effective to create an inhospitable space for these organisms.


While a good quality filter on your pool is a given for many reasons, among them is preventing the introduction of algae spores. Blooms do not appear spontaneously, and preventing the introduction of spores in the first place is key to preventing larger blooms. Be sure to check, replace, and clean your pool filter regularly to avoid a need to treat your pool.


All kinds of fountains can experience algae build up, but some may be more prone to the issue than others. Fountains that do not contain standing above pools for recirculation are less prone, as there is a smaller window for spores to be introduced. Still, all fountains should be regularly maintained to avoid algal blooms.

A fountain shows signs of algae build up.

Avoid Sunlight

Though viewing the sun on the water can be pretty, full sunlight can create favorable conditions for algae to bloom. Consider installing your water feature in an area that experiences full or partial shade.

Use Filtered Water

Contaminants are one of the greatest sources for algal spores. For this reason, consider replenishing your fountain with only filtered water that is free of growths found in pools or rainwater.

Regular Cleaning

Both surface and deep cleaning can go a long way towards getting rid of and preventing growth. Be sure to drain your fountain and wipe clean with soap and water, or a diluted bleach mixture on a scheduled basis. Not only does this prevent unwanted plantlife from taking hold, but it can improve the look and longevity of your fountain overall.


Treating your water with appropriate chemicals as you would a pool can be a great way to prevent algae build up in almost any fountain. While there are many on the market, DIY solutions that are plant and animal safe can also be accessed, as discussed below.


Even the smallest water features can support algal blooms. If you’ve ever maintained a backyard birdbath, you know how hard it can be to keep them clean. While many chemicals are unsafe for animals, there are many things you can do to prevent your bird oasis from becoming a swamp.

Clean Regularly

Because birdbaths are regularly prone to contamination from their feathered visitors, sometimes preventing larger algae problems comes down to eliminating the smaller spores. Especially in warm seasons, cleaning your birdbath weekly can greatly help to reduce the formation of algae and other grime and build up. Animal safe solutions can be bought or made at home using common ingredients such as white vinegar.

Biodegradable Algae Control Balls

A bird splashes in an algae free bird bath.

Larger bird baths may benefit from the use of biodegradable algae controls balls which remain in your fixture at all times and are not harmful to plants or animals. This is one of the easiest forms of prevention as it requires very little active action, other than to replace needed. This same technique can be used in conjunction with other methods in ponds or other wildlife accessible features.

Change Water Frequently

The key to keeping a birdbath not only clean, but safe and appealing to your local birds, is to change the water frequently. Dumping, rinsing, wiping, and refilling your birdbath at least biweekly can greatly reduce grime, dirt, and agal blooms. Additionally, you’re likely to see more feathered friends visit your installation.

Place it in the Shade

One of the advantages to this water feature is it’s exceptional portability. Because birdbaths can be placed almost anywhere around the yard, choosing to place them in shaded areas can help you to prevent favorable conditions such as bright sunlight.


One of the most common algal offenders, those with backyard ponds may have more trouble preventing green water and blooms from occurring. Due to the exposed nature and frequent opportunity for contamination, algae spores can easily find their way into these water features and multiple quickly. Thankfully, understanding how to prevent and treat algae can help homeowners avoid overwhelming algal issues later on.

A backyard pond collects algae.

Add Plants

One of the most effective and aesthetically pleasing solutions to excess algae growth in your pond may come from an unexpected source. Adding water plants to your pond, especially those containing fish, can help you to manage nutrient build up. By absorbing excess nutrients, the algae is starved of the resources it needs to grow. Plants such as lilies and lotus block the surface of the water from excess sunlight, while submerged plants such as hornwort absorb nutrients within the pond.

Water Treatments

Many water chemical water treatments can help to reduce algal bloom and prevent spores from taking hold in your pond. For ponds that have no fish or living material in them, chemical treatments can be generally used without concern. If you are hosting fish or other species in your pond environment, it is important to use balances that do not affect the health of these organisms. Natural solutions such as adding hydrogen peroxide, or using formula that are veterinarian approved will prevent issues.

Ultraviolet (UV) Clarifiers

If you’re looking to avoid the chemical route, you can help prevent green water and algae buildup in your pond by using the natural powers of UV. Though algae thrives in natural sunlight, exposing the plants to very high levels of UV can kill them. This is a great way to to control plant matter accumulation without chemicals.

Linings and Preventing Contamination

One of the largest contributing factors to algal bloom in ponds is that they are especially vulnerable to outside contaminants. Keeping your pond liner clean and properly maintained will keep outside contaminants from entering from sources such as groundwater and soil. If you have regular wildlife visitors to your pond such as deer or raccoons, creating a physical barrier to make it less accessible can help to prevent spores from finding their way into the space.

Preventing Algae is Easier Than Clearing It

When you commit to installing a water feature, you are also committing to the work it takes to upkeep one. Proper cleaning, maintenance, and understanding the conditions that breed algae are key to preventing them. Once large algal blooms have grown, it can be difficult to get rid of them.

Thankfully, with some know how and a few tricks and tips, you can prevent any outdoor water feature from turning green.

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