Swimming Pool Turning Green? Here’s Why.

There are many challenges that come with owning a pool, and one of them is keeping water crystal clear. It’s not unnatural for a pool to suddenly turn green. In fact, this problem can sometimes spring up overnight with little warning, even if you are cleaning your swimming pool on a regular basis.

So how do you stop it from happening? If you are eager to evade the green slime that can quickly take over your pool, leaving a film of sludge along the bottom and contaminating the water, keep reading to learn about the most common causes of your pool looking more like grass than water:

• Low Chlorine Levels

Chlorine is a chemical that is added to the water of most swimming pools to prevent the growth of bacteria and algae. If there is little or no chlorine in the pool water, it is easy for algae and bacteria to grow, which can cause the color of the water to change. The bright green color is usually caused by algae bloom, which can spread quickly. This algae grows best in warm water and sunlight, so it’s important to remember to treat your pool with chlorine and ensure it is protected, otherwise you’re inviting the algae bloom to spread rampant. 

• Accumulation of Pollen

When it's the right season for it, pollen can be found on everything outside, from the swing set to the sidewalk to your pool. Pollen often builds up on the surface of swimming pools and can cause the water’s surface to have a nasty, yellow-green tint. Any pollen that has blown into the pool can be difficult to retrieve, because it is too small to be removed by the filter. Though your pool may look unappealing, pollen is harmless to the pool and won’t affect you unless you have pollen allergies.

• Oxidized Metals in the Water

You may not be able to see it with your eyes, but if your pool is turning green, one likely explanation is that there is a lot of metal in the water. There are many ways for it to get there, but two of the most common are when metals come in through your water source, or through the use of cheap algaecides. As the metals oxidize in the water, it can cause the pool to take on a greenish tint. If high levels of oxidized metals in the water aren’t addressed, it can lead to staining of the pool’s finishing. To test the levels of oxidized metal in a pool, pool service companies will often shock the water. If the water turns green, it is an indicator of too much metal.

• High pH

A high pH level is not good for your pool because it can make chlorine treatments ineffective and allow algae or bacteria to grow. There are many things that can increase the pH of pool water such as cosmetics from swimmers, dirt, oils, and the weather.  When left untreated, a high pH can cause damage such as skin rashes, as well as cloudy water.

• Lack of Cyanuric Acid (CYA)

Cyanuric acid is added to pools to help make the chlorine last longer. Chlorine can only last for a limited amount of time before it is ineffective. The CYA bonds with the chlorine to keep it from being evaporated so fast. Not enough CYA means that your chlorine treatment won’t last for very long, and your pool is rendered unprotected from algae and bacteria. On the other hand, too much CYA added to the pool can also keep the chlorine from working how it should. To help figure out the right balance, consult with expert pool service technicians who can point you in the right direction. 

• Inadequate Filtration and Circulation

Filtration systems are meant to filter out contaminants and keep added pool chemicals like chlorine circulating. If the system doesn’t work correctly, the pollutants that get in could negatively affect your pool, and the chemicals in the water may not be able to do their job properly. Other than having an adequate filtration system installed, the best way to keep your pool protected is by knowing how long you should run the filter for best results.