How To Remove Dead Algae

Dead Algae In Pool - How To Remove Them?

Some types of algae infestations can be difficult to treat, so many pool owners are not pleased to learn that algae cells can linger in your pool long after the algae itself has died.

Dead algae in your pool that is left unattended can cause unsightly looking stains and can also accumulate as an algae dust in the bottom of your pool.

In this article, we will discuss the different causes of accumulations of dead algae, and provide a list of steps that you can take in order to remove dead algae from your pool.

We also include information about both chemical-using and chemical-free methods for cleaning up dead algae in order to best suit your preferences.

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Causes of Dead Algae Accumulation

Use Of Shock & Algaecides

Dead algae can accumulate in your pool following the use of algae treatment methods such as shock products and algaecides.

These products cause algae cells to die off in mass, which can cause them to become detached from surfaces. Scrubbing your pool can also cause dead algae to break free and gather at the bottom of the pool, and also gets dead algae particles in the water column.

If your pool has had a period of chronically-low chlorine levels that you are now working to correct, this can also cause an unexpected accumulation of dead algae, even if none was visible before.

This is because algae multiplies rapidly in the water column when low chlorine levels are present, but will die and fall to the bottom as dust when chlorine levels are restored to normal.

Insufficient Filtering & Cleaning

The accumulation of dead algae in your pool can also be caused by issues with your filter, or a lack of proper vacuuming following algae treatments.

By not running your filter for the recommended minimum amount of time of eight hours per day, you are allowing dead algae to remain in your pool as it decomposes, creating unsanitary conditions.

If you have been running your pump enough, you should also ensure that all pieces of your pump and filter are working correctly, and that your filter is reasonably clean. Filters can fill up with dead algae faster than you may expect, and may need to be rinsed off with clean water in order to resume cleaning your pool’s water effectively.

Dead algae dust that is left unattended on the lining or in the bottom of your pool can also lead to organic stains, which are more difficult to remove than dead algae alone. We recommend removing dead algae as soon as possible to avoid developing these stains.

How to Remove Dead Algae From Your Pool

In order to remove dead algae from your pool, you will want to start by scrubbing affected areas of your pool’s lining with a stiff bristled brush.

If you have a concrete or pebblecrete pool, you may choose to use a wire-bristled brush, but these are not recommended for pools that may become easily scratched.

After scrubbing areas of dead algae on the surface of your pool, use a vacuum to collect large amounts of algae dust that has gathered at the bottom of the pool.

You may also combine vacuuming and scrubbing by using a flexible brush vacuum head.

After scrubbing and vacuuming, your water may appear dirty due to the stirred up debris. Allow your filter to run for at least six hours to see if water clarity conditions improve with time. If the water does not become clear, we recommend using a clarifier.

Clarifying products like the Algon Clarifier are specifically made to remove tiny particles of debris, such as dead algae dust. This product works by causing small pieces of debris in your pool to stick together. In larger masses, the debris can be removed by your filter system more efficiently.

If there are still dead algae spots along the lining and bottom of your pool after following these steps, your pool may have developed organic stains. Luckily, although these stains are not as easily scrubbed away as dead algae, they can be scrubbed away with enough elbow grease.

If scrubbing isn’t your thing, try using a stain removing product that works on organic stains. The Serious Stain Remover works on metal and organic stains and is safe for nearly all types of pool lining.

You simply add this product to your pool and leave your pump off for the recommended length of 2-3 days in order to remove your dead algae stains without any scrubbing.

For more detailed instructions, check out this guide on how to remove algae stains from pool walls.


Dead algae can build up in your pool following the use of algae treatments. While it is more common to notice dead algae accumulation after killing off a large infestation, you may also see it build up over time if your filter is not removing it properly.

Do you have any questions about how to remove dead algae from your pool? Leave us a comment, we’d love to help!

Louis from Pool Advisor


A chemical engineer by trade, Louis is committed to debunking myths in the pool industry by explaining the underlying chemistry and making it accessible to all.