Top 10 Algae Prevention Tips


Nearly every pool owner has had to deal with algae problems at one time or another. Even with a properly-working filtration system, sanitizers at their recommended levels, and a watchful eye, algae blooms can still develop. Algae spores can enter a pool in a variety of different ways, but is most commonly introduced into a pool through wind, rain, dirt, and even on a swimmer’s body or bathing suit. Keeping algae spores out of your pool is impossible, so it is important to prevent the microscopic spores from turning into unsightly algae blooms. Maintaining clean, algae-free water will help keep your pool and your family happy and healthy, and Leslie’s is here to help prevent and protect your pool from any algae problems!

Leslie’s has compiled a quick and easy-to-read list of tips for preventing and eliminating algae. We are also proud to offer our 5-Year Algae Free Guarantee that promises to help you keep your water clean and clear. For more comprehensive information on algae prevention and our Algae Free Guarantee, please visit the Leslie’s Help, My Pool Is Green page, visit your nearest Leslie’s Store , or call us at 1-800-LESLIES.


1. Make sure your circulation system is running properly
A circulation system in good working condition is one of the most important steps to preventing algae growth. To keep your circulation system running properly, you will want to regularly check and clean the skimmer and pump strainer baskets. This will keep the water and the sanitizing chemicals flowing evenly throughout your pool.
Along with emptying the skimmer and pump strainer baskets, it is also important to routinely clean or backwash your filter. Over time, filters become clogged with dirt and debris, and require some simple maintenance. No matter what type of filter you use, it is necessary to clean your cartridge filter or backwash your sand or D.E. filter whenever the pressure gauge reads 8-10 psi higher than normal. When cleaning or backwashing, Leslie’s recommends using a specialized cleaning aid to help you get the most out of your filter. Leslie’s DE Filter Cleaner, Sand Filter Revitalizer, and Cartridge Cleaner will help make cleaning a breeze and keep your filter working properly all season.
During swimming season, Leslie’s recommends running your pump and filter between 6 and 8 hours a day, and you can even increase the cycle to between 10 and 12 hours during times of heavy swimmer usage. Routinely checking and cleaning your skimmer, pump, and filter will help keep your pool clean and algae free.

2. Always keep sanitizer within the desired range
Algae spores are constantly finding their way into your pool, but are usually killed by the chlorine or other sanitizers before they ever grow into blooms. However, when the sanitizer levels get too low, these spores can quickly grow and begin to cling onto pool surfaces. If you use chlorine to keep your pool sanitized, the level should stay between 2.0 and 4.0 parts per million (ppm). To help maintain a safe and effective level of chlorine in your pool, Leslie’s recommends using either an automatic or a floating chlorinator . Both automatic and floating chlorinators feed a constant amount of chlorine into your pool, and prevent the chlorine level from dropping below the effective range. If you are using another type of sanitizer, make sure it is also within the desired range.


3. Shock the pool weekly
A weekly shock of your pool is great for eliminating any algae spores your regular sanitizer might have missed. Using a shock like Leslie’s Power Powder Plus, or a granular chlorine like Leslie’s Chlor Brite, is a great way to keep your pool clean, your sanitizers at their correct levels, and should help to eliminate any potential algae problems before they grow. Using a non-chlorine oxidizer, like Leslie’s Fresh ‘N Clear, is another method of weekly pool treatment. Fresh ‘N Clear will help to give your present chlorine levels a boost, making your sanitizer more effective at preventing algae growth.


4. Develop and maintain a scheduled brushing routine
Pool walls, floors, and steps are the most common places to find algae in your pool. If left untreated, algae can burrow their roots inside the cracks on these surfaces, making them very difficult to remove. Brush the pool walls, steps, and floor at least once a week (more if necessary) to prevent algae growth from forming in your pool.

5. Find the right brush for your pool
Brushing and scrubbing your pool walls are necessary to prevent algae growth, but the wrong kind of brush can do serious damage to your pool surface. If you own a vinyl-lined, fiberglass, acrylic, or painted pool, you will want to use a nylon brush. These brushes are softer and won’t tear the vinyl or scratch the surface. For plaster or concrete pools, a wire brush will provide superior cleaning strength without harming the pool surface.

NEVER use a metal wire brush with a vinyl-lined, fiberglass, acrylic, or painted pool. Wire brushes are very abrasive and can cause the pool surface to rip, tear, or scratch. Always use caution and be careful not to apply excessive pressure when using a wire brush, even on plaster pool surfaces.

6. Use a vacuum to remove dirt and debris
Along with brushing and scrubbing, vacuuming your pool is a great way to help prevent algae growth. Brushing the pool walls will dislodge most algae spores that are clinging to the surface, but these spores often simply settle at the bottom of the pool. Using a vacuum, or one of many Automatic Pool Cleaners that Leslie’s offers, you can eliminate most of the dirt, debris, and contaminants that find their way into your pool.


7. Use an algaecide regularly
Regular use of an algaecide is a great way to help keep algae from ever taking hold in your pool. There are many different types of algaecides available, designed to help fight certain kinds of pool algae. Algaecides are designed to be used when your pool is clean and algae-free, and will stop algae spores from developing into full-on blooms. To help stop algae before it ever shows up, we recommend using Leslie’s Algae Control, an easy-to-use, multipurpose algae preventer that is safe for most types of pools.


8. Eliminating phosphates prevents algae growth
Algae, like all plants, are living creatures that require food and nourishment to survive. Phosphates, which can enter your pool through dust, leaves and debris, and swimmer waste such as sweat or oils, act as fertilizer for algae, allowing spores to grow into fully-developed algae blooms. By eliminating phosphates, you can stop the growth of algae before it ever begins. Pool Perfect + PHOSfree is made from 100% natural and safe enzymes, and is designed to help keep your pool algae-free by getting rid of the phosphates in your pool. Just 1 ounce of Pool Perfect + PHOSfree per 2,000 gallons of water, added weekly directly into the skimmer, will help to eliminate phosphates and prevent algae growth.

9. Use Pool Magic + PHOSfree when closing pool for the winter
Even when your pool is closed for the winter season, algae can still take hold of your water. A week before closing your pool, add one bottle of Pool Magic + PHOSfree for every 20,000 gallons of water, directly into your skimmer. Not only will this keep your pool clean and algae-free all winter long, but it will help you have a quick and easy opening when the warm weather returns. Repeat the process of adding one bottle for every 20,000 gallons when opening your pool to help ensure an algae-free swimming season.


10. Keep a watchful eye on your pool all year long
The two most important steps in owning an algae-free pool is to maintain a cleaning schedule and to watch for any signs of algae growth. Keeping your maintenance schedule will keep nearly all of the algae spores from developing into blooms, but you should always be watching your pool for any algae that may be growing in hard-to-see areas like pool steps or ladders. This also means frequent check-ups of your pool even while it is closed for winter. Clean and check your pool regularly and you should have an algae-free pool and happy swimmers!

Always use caution when cleaning and adding chemicals to your pool. Never mix chemicals before adding them to your pool, and always read directions and follow the instructions provided by the manufacturer to ensure the highest level of safety.