Algae is a versatile organism that can thrive in a variety of environments. While it can grow during winter, the growth rate is slower than during other seasons due to colder temperatures and shorter days.
In colder regions, such as the Arctic, where there is less available light and temperatures remain below freezing for much of the winter, algae can find it difficult to access the energy they need to grow. Many types of algae require sunlight to photosynthesize, and the winter months have fewer hours of daylight, making it challenging for these algae to receive the energy they need to survive and grow.
In contrast, swimming pools provide a warm environment and constant access to sunlight, allowing algae to grow even in winter. However, the colder temperatures and shorter days mean that the growth rate of algae is slower during this season compared to other seasons.
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Can You Close Your Pool For The Winter With Algae In It?

As you may know, winter weather does not eliminate algae growth in your pool, but it does slow it down. If you close your pool for winter with algae present, the growth of algae will be reduced, but not completely eliminated. Therefore, it is crucial to address the issue of algae before closing your pool for winter to prevent further problems.
So, what can happen if you don’t clean pool algae before closing?
If you don’t clean the algae before closing, then it will endure through the winter and may even spread further. This can be a problem when you open the pool in the spring, as it could be significantly worse than when you closed it.
Does Black Algae Die In Winter?
Black Algae known as Audouinella is an algae that is found in both fresh and saltwater ecosystems. Black Algae can easily survive in cold water and therefore does not die in winter.
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That is why it is often found in cold water such as lakes, ponds, and pools.
How To Prevent Algae In Pools Over Winter?
When it comes to keeping your pool clean and free of algae over the winter months, prevention is key. Here are some steps you can take to ensure your pool stays free of algae during the cold season:
Use Algaecide:
Using an algaecide formulation in your pool is one of the best ways to prevent algae growth over winter. Algaecides work by killing the existing algae and preventing new algae from growing. There are many good algaecide products available, so make sure to select one that is specifically designed for winter use.

By Shock:
Using a shock treatment in your pool will prevent the algae from growing by raising the chlorine level to an optimal range for killing off any residual bacteria or other contaminants. It’s important to shock your pool regularly during the winter months and, as always, make sure you follow the instructions on the product.
Other Methods:
There are methods to prevent algae growth in your pool: regular cleaning, balancing water pH levels, maintaining the filtration system, and adding enzyme clarifiers. We highly recommend using algaecide to prevent the growth of algae over winter, as it works by killing existing algae and preventing new growth. Any missed algae can continue to spread until the spring season, making it harder to maintain a clean pool during winter. Therefore, it’s important to use algaecide in your pool regularly to keep it algae-free during the winter season.
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