Algae Removal and Prevention Part 2

Note: A newer and more up-to-date version of this article can be found here.

This Leslie’s Swimming Pool Supplies video will teach you how to remove and prevent algae to make sure it never comes back.

  • Chlorine can help kill and prevent algae
  • Clean your filter before adding any chemicals to your pool
  • Make sure you test your water on a regular basis
  • Leslie’s has chemicals to combat any type of algae


If you have any other questions about algae, visit or reach out to one of  our knowledgeable staff members at one of our store locations.

Video transcription:

Hi I'm Lauren. Here at Leslies we've been serving the needs of do it yourself pool owners since 1963. we believe every pool owner care for and maintain their own pool with help from the experts at Leslies.

Today I will be showing you some simple and easy steps on how to remove and prevent algae growth in your swimming pool. Having algae in your swimming pool can cloud the water, make the pool service slippery, stain the pool surface and clog the filter. Algae can also create health risks because it hides bacteria and viruses. The algae that grows in your swimming pool can come in three different forms.

Green algae, yellow or mustard algae and black algae.

To treat the green algae in this pool, we will be using Green to Clean. While not required when using green to clean, brushing me algae first can speed up the removal process by loosening the algae from the pool walls, floor and steps. Green algae can grow in any part of your swimming pool. If there is algae present in your pool, this means you most likely have no sanitizer such as chlorine in your water.

Since most pool owners use some type of chlorine as their primary sanitizer. We’ll show you how to remove algae from a chlorine pool. chlorine is the first line of defense in preventing algae growth and is also an effective algae killer. In order to remove green algae from your water, we recommend using Green to Clean and a chlorine based shock like Leslie's Power Powder Plus or Leslie’s Chlor Brite.

How much you add of either green to clean or shock is determined by how many gallons of water in your pool. Be sure to read and follow all label directions when adding chemicals to your pool. Green to clean is a granulated chemical formula that when combined with chlorine shock will remove and kill any existing algae in your pool. Before you add any chemicals clean your filter.

To remove algae, your pump and filter will need to run continuously for about 48 hours. Do not mix green to clean in water or with other chemicals prior to adding it to your pool. Broadcast half of the prescribed amount evenly around the perimeter of the pool. Starting with the problem areas then pour the remaining half directly over the problem area. After adding green to clean wait five minutes, then add chlorine shock directly to the pool.

Let your pool pump run for the next 12 hours. After 12 hours add a second equal dose of chlorine shock to your swimming pool to keep the chlorine level high. Wait another 12 hours and then add a third equal dose of chlorine shock. After the third dose of shock, wait 12 hours and then turn your pump off.

Adding Natural Chemistry’s Pool First Aid helps remove the dead algae from your pool and it’ll make your water crystal clear. Pour the recommended amount directly into the pool while walking around the perimeter. After using green to clean we recommend back washing your sand or DE filter or cleaning your cartridges to clear the dead algae out if your filter.

If you have any lingering issues of algae in your pool bring a water sample into your nearest Leslies store for a free test and analysis.

If your pool has mustard or yellow algae follow the same instructions using Yellow Out. You can also use Leslie's Algae Control, Copper Algaecide or Silver Algaecide to remove green or yellow algae.

These are liquid chemicals and the directions for these products are different. Again make sure you read and follow all label directions when adding chemicals to your pool.

The third type of algae that can be found in your swimming pool is black algae. Black Algae is the most difficult algae to control and eliminate. It is usually found on the bottom of your pool and small raised black spots. The best way to remove it is with Leslies Black Algae Killer.

Leslies black algae killer contains copper. Make sure to have your pool water tested for metals. Before adding Leslies black algae killer, remember to loosen up algae by brushing it thoroughly. If you're swimming pool is slightly cloudy after using an algae treatment, you can use Natural Chemistry’s Pool first aid, Leslie's Ultra Bright or Leslie's fresh and clear non-chlorine oxidizer to clear up your pool water. These products will help make the water crystal clear.

You may be unaware but there can be nutrients in your pool water that feed algae. These nutrients are called phosphate and it is best to keep them at the lowest possible level at all times. Phosphates come from organic matter in your pool such as leaves, dirt or any other debris. In order to eliminate or reduce the phosphate level in your pool use Natural Chemistry’s Pool perfect and PhosFree regularly. Simply pour the recommended dose into your skimmer while your pool pump is running. Eliminating phosphates from your pool is one of the easiest and most effective ways to keep your water algae-free.

Make sure you keep your pool sanitizer at the desired range. For pools using chlorine, keep your chlorine level between two and four parts per million. Keeping your pool sanitized and phosphate free helps prevent algae before it has the chance to grow.

Every Leslies Store carries a variety of algae control and prevention products to keep your swimming pool algae free. In fact we are so confident about our products that Leslies offers five-year algae free guarantee for your pool water if you use our recommended products. Follow the directions and have your water tested regularly at Leslies.

We hope this video has shown you some simple ways on how to remove and prevent algae growth and your swimming pool. Our goal here at Leslies is to make pool care easy.

Thank you for watching.

For more information please visit our website at or any one of our more than 800 stores


Facebook  Twitter  YouTube  Instagram