What Causes Swimming Pool Algae and How to Prevent Them

Are you thinking about what is swimming Pool ? Swimming pools can be great fun to have in your backyard, and they are quite profitable in the summers, but they can get dirty quite easily. And a little dirt is all that need to grow.

Does your pool have patches of green in it? That likely means it’s infested with . Water ought to be blue and beautiful, and patches of green in them are the last thing anyone wants to see in their pool, and if it’s a public one, you’re likely to start losing customers fast if you don’t do something about them. 

swimming pool algae
Michael Trolove / Green soup at the swimming pool / CC BY-SA 2.0

What are Algae and Why are They in Your Pool?

Algae in your pool are one surefire way to know something is wrong somewhere.

They’re actually nothing more than primitive plants; plants that haven’t made it past the unicellular stage. They don’t have roots, leaves, or stems, so they make their food through photosynthesis. Unfortunately, this means all they need to thrive is some sun, water, and trace amounts of nutrition – all things which public pools (and private pools, but especially public ones) have too much of.

You’re probably wondering where the nutrition in your pool is coming from. It’s the dissolved food particles from swimmers and customers (usually the kids, but some adults can be nasty like that) that the algae use as start-up capital to get on their metaphorical feet and have photosynthesis take over. And there’s no avoiding the algae, either, not when they reproduce by throwing around their dandruff-like children (spores) everywhere to be fruitful and multiply wherever they can.

There are many types of algae, but one type which tends to be found in swimming pools and can’t keep its hands to itself is called cyanobacteria. Cyanobacteria (sometimes referred to as blue-green algae) live in oxygen-free environments where there isn’t much competition from other organisms for nutrients. This allows them to grow quickly and spread throughout your pool. As cyanobacteria spread through your pool, they will often coat everything in sight including your swimsuit, hair, and skin. When cyanobacteria touch these surfaces, they release chemicals known as endotoxins which can irritate eyes and skin causing eye infections, rashes, and even burns. The only way to prevent these harmful effects is by keeping on top of the algae situation in your pool!

Causes of Algae in Swimming Pool

There are many reasons why algae dandruff might find your pool a fertile spot to grow. We will explore a few of them in the next few paragraphs.

Unbalanced pool chemicals

The most common cause of algae is swimming pool chemicals that aren’t properly balanced. All pools need a combination of shock treatment and a chlorine-based sanitizer, as well as balanced levels of pH, alkalinity, calcium hardness (or total hardness), cyanuric acid, stabilizer (sulfur), and oxidizer (bromine). If these elements are either too high or too low, it will make it easier for algae to form. Make sure you have a good chemical balance before you start treating your pool with an algaecide.

Plentiful sunlight

Another major cause of algae is having an overabundance of sunlight hitting your pool water surface. Sunlight can heat your water, making it more hospitable for algae growth. That’s not mentioning how algae need the sun’s rays to carry out photosynthesis.

To prevent algae from forming on sunny days, try adding some shade to your swimming area using umbrellas or tree branches placed around its perimeter. Some swimmers like to add floating pool toys to their water to help create an appealing barrier between the sun and water. But if you’re looking for an easy way out, consider investing in an automatic pool cover – they work wonders at preventing excessive heat from entering your pool. 

Poor pool filtration

Yet another factor that enables algae to thrive is poor filtration methods. If there isn’t enough filtration taking place inside your filter system, then debris and other matter will build up along the bottom of your swimming area instead of being filtered out. This buildup serves as baby formula for algae until they are mature enough to fend for themselves. Make sure you keep your filters clean so they can do their job effectively.

Once you know what causes algae to grow in pools, preventing it becomes much simpler! It all comes down to keeping everything balanced and clean so that nothing gets out of hand.

How do you Keep Algae Away?

You can’t keep algae from growing in your pool, especially if it’s a public one. But you can make sure they work hard – really hard – for their survival. All you need to do are the following:

Keep on top of your pool chemical situation

Chlorine is usually your first line of defense against algae growth. If you know your pool has been exposed to algae, start with a shock treatment followed by several days of keeping chlorine levels above 3 ppm.

You can also use copper or silver ionization, which provides additional protection against green water algae and should be added after shocking if your goal is getting rid of algae growth. It’s also important to maintain proper pH levels, as low pH can encourage algae and bacterial growth (if you find some unsightly slime, it’s bacteria chilling in your pool; time to break out the chemicals).

Watch your pool’s pH

Maintaining an pH (between 7.2 and 7.6) will help ward off unwanted algae, and harmful bacteria as well will find your pool a barren land (that’s actually a good thing in this context).

Maintain good filtration methods

Make sure your filter is working properly – if it isn’t, you may not be able to adequately filter out particles that provide food for algae growth. Cleaning your filter regularly will help remove any accumulated debris that might otherwise serve as food for growing algae colonies.

If you’re still having trouble preventing algae growth despite maintaining good pool chemistry and using a functioning filtration system, try installing an ultraviolet light unit on your pump; UV rays can effectively kill most microorganisms, including algae.

swimming pool algae

While algae infestations are natural for any swimming pool (you can even refer to it as a rite of passage), they aren’t the most healthy of organisms to share bath space with. By controlling some of their most common causes, you’ll be able to help prevent swimming pool algae from building up in your pool. Even if you experience something like an algae bloom, immediate action should nick that in the bud.