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3 Steps to a Healthy Pool: Sanitize, Shock, Prevent

Swimming pools are an excellent source of fun, relaxation, and exercise during the summer season. Pool maintenance is a crucial part of maintaining a clean, safe, and beautiful pool, but it doesn’t have to be challenging. Of course, there's the routine water testing and balancing, pool cleaning, and ensuring adequate circulation and filtration. However, it’s important for pool owners to understand the importance of keeping your water free of germs and algae with three simple steps: 

floating chlorine dispenser

1. Sanitize

Leslie's Pool Shock

2. Shock

Leslie's Perfect Weekly Bottle

3. Prevent

In this article, we will discuss how to properly sanitize your pool water daily, shock the water weekly, and prevent algae from taking over.

Step 1: Sanitize Daily for Healthy Pool Water

Get healthy pool water with Leslie's 3" Jumbo Tabs

Sanitizing pool water keeps it safe and healthy for swimmers, eliminating bacteria, viruses, and other harmful microorganisms that can cause illness and infection. Leslie's 3" Jumbo Tabs are one of the most popular and effective ways to sanitize pool water on a daily basis.

Leslie's 3" Jumbo Tabs are stabilized trichlor tablets that dissolve slowly in water, ensuring a consistent level of Free Available Chlorine at all times. This steady level of chlorine is crucial for controlling germs, algae, and other microorganisms in the pool. Trichlor tablets contain the stabilizer Cyanuric Acid, which protects chlorine against breakdown under the sun’s harsh UV rays.

To use Leslie's 3" Jumbo Tabs, simply place them in a floating chlorinator or an inline or offline automated chlorine feeder. Contrary to popular belief, you should never place 3” chlorine tablets inside your skimmer basket! Doing so can damage your skimmer and pool equipment. Check your chlorine dispenser once a week and keep it filled with the correct number of tablets. The amount of tabs required will depend on the size of the pool and the desired chlorine level. Check the product label for guidelines and usage instructions. 

Test your water often — at least once or twice per week. Always maintain a constant Free Available Chlorine level of 1–4 parts per million (ppm) for safe and healthy pool water. If your chlorine levels are routinely low, you may need to increase your daily sanitizer dosage. Low chlorin can also indicate an issue with high chlorine demand — which leads us to our next point!

BONUS TIP: Alternative sanitizers can help reduce the amount of chlorine tablets needed to sanitize your pool. Mineral systems and saltwater chlorine generators are just a couple of the more popular options.

Step 2: Shock the Pool Weekly

Shock the pool weekly for healthy pool water with Leslie's Power Powder Plus 73 cal-hypo pool shock

Even if you maintain a consistent level of 1–4 ppm Free Available Chlorine, organic contaminants and chloramines can still build up in a short amount of time. This leads to cloudy water, skin and eye irritation, and a strong, unpleasant “chlorine” odor near the pool. But not to worry! This is where shocking the pool comes into play. Using pool shock is an effective way to destroy organic contaminants and other harmful organisms. It's essential for a healthy, sanitized pool. 

In general, we recommend shocking the pool once a week to keep your pool water clean, safe, and beautiful. The type of shock you use depends on the situation and where your pool’s Free Available Chlorine levels are. 

If you’re dealing with algae or some type of major contamination, or if your chlorine levels are below 2 ppm, a chlorine shock works best. If using stabilized 3” chlorine tablets as your daily sanitizer, we suggest using an unstabilized shock, such as Leslie’s Power Powder Plus 73. On the other hand, if this is just a routine weekly maintenance shock, and your Free Chlorine is at least 2 ppm or higher, a non-chlorine oxidizing shock like Leslie’s Fresh ‘N Clear can help break down non-living organic contaminants and prevent chloramines from forming. As an added bonus, you can swim as soon as 15 minutes after using Fresh ‘N Clear.

When using any type of pool shock, always read and follow all product label instructions. In most cases, it’s best to shock the pool at night. This allows the shock to work most efficiently, and ensures that the chlorine has enough time to work. Overnight shocking also gives the chlorine levels a chance to return to normal before swimmers use the pool again.

Step 3: Prevent Algae by Removing Phosphates

Leslie's Perfect Weekly is a 3-in-1 maintenance chemical to help you maintain healthy pool water

Algae growth is a common problem in swimming pools. Not only is a green, algae-filled pool unappealing, it also indicates a problem with improper water balance, circulation, and/or sanitization. If you have algae in the pool, it means the water isn't healthy for swimming.

Algae thrives in warm, moist environments. It can grow quickly in pool water that is not balanced, circulating, or adequately sanitized. But even the most well-maintained pools can still fall victim to this aquatic microorganism. Leslie's Perfect Weekly helps prevent algae growth and keeps pool water clean and clear with a proprietary 3-in-1 maintenance formula.

Phosphates are a food source for algae, and their presence makes it easier for algae to grow. Phosphates can enter your pool through a variety of sources. These include plant debris, soil, certain stain and scale products, cosmetics, sunscreen, laundry detergent residues, cleaning supplies, and even plain ol’ tap water. Leslie's Perfect Weekly contains a phosphate remover to eliminate phosphates from the pool water. Perfect Weekly also contains enzymes to help reduce chlorine demand, and a liquid solar cover to reduce water and chemical evaporation. This 3-in-1 functionality makes it a smart addition to any pool care routine. 

Regular use of Perfect Weekly can help prevent algae growth, reduce the amount of chlorine required, conserve water, and keep the pool water looking and feeling clean. Simply follow the product label instructions for the weekly maintenance dosage and application instructions. Because Perfect Weekly contains enzymes, wait to add this product to the pool until your Free Available Chlorine levels are back below 5 ppm after shocking your pool.

BONUS TIP: Leslie’s Perfect Weekly is just one item that can help improve chlorine efficiency in your pool. Check out our Resource Center article for more tips!

Other Tips to Maintain a Healthy Pool

In addition to the steps listed above, there are a few other pool care tasks all pool owners must do.

  • Clean the pool: Regularly skim debris from the water surface and floor. Then, brush all pool surfaces, and manually vacuum the pool as needed to keep it nice and clean. This will help keep your chlorine working efficiently, and can help prevent issues with organic stains and algae. An automatic pool cleaner can help reduce the amount of time spent on manual cleaning.
  • Test and balance water: At least once a week, test the water to make sure all aspects of water chemistry are in balance. If anything is out of range, use water balancers to make adjustments. You can use an at-home test kit to keep an eye on basic elements. You can also bring a water sample to your local Leslie’s for a FREE in-store AccuBlue® water test and customized treatment plan. Leslie’s AccuBlue precisely measures 10 different aspects of water chemistry, and is the most comprehensive and accurate pool water test available.
  • Circulate and filter the water: Make sure to run the filter pump long enough each day. For most pools, it takes about 8–10 hours to move all the pool’s water through the filter. Increase this time during periods of high usage or hot temperatures. Check the pressure gauge on your filter weekly, and clean the filter whenever the pressure reads 8–10 psi higher than the starting “clean” pressure.
  • Empty the baskets: Frequently check your pump strainer and skimmer baskets. Gently remove or rinse out the debris as needed. This keeps your pump and filter working efficiently by improving water flow and preventing a suction side blockage. If you notice the basket is cracked or damaged, replace it.


Maintaining a clean, safe, and beautiful swimming pool requires diligent, regular maintenance, including sanitizing daily, shocking weekly, and preventing algae growth by removing phosphates. Leslie's 3" Jumbo Tabs, Power Powder Plus 73, Fresh ‘N Clear, and Perfect Weekly are all effective water maintenance products that can help keep the water healthy and safe for swimmers.

Following these tips and using these products each week can help ensure a swim season full of fun, relaxation, and exercise in a healthy, algae-free swimming pool. If you ever have questions or run into any problems with your pool, just stop by your local Leslie’s to chat with one of our experts. While you’re there, bring in a water sample for a free in-store AccuBlue test, and we’ll walk you through your step-by-step customized water treatment plan if anything is out of balance.

Recommended Products

Bucket of Leslie's 3


Leslie's Power Powder Plus 73 Chlorine Shock


Leslie's Perfect Weekly


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Leslie’s makes every effort to provide accurate recommendations based upon current ANSI/APSP/ICC-5 2011 (R2022) standards, but codes and regulations change, and Leslie’s assumes no liability for any omissions or errors in this article or the outcome of any project. You must always exercise reasonable caution, carefully read the label on all products, follow all product directions, follow any current codes and regulations that may apply, and consult with a licensed professional if in doubt about any procedures. Leslie’s assumes no legal responsibility for your reliance or interpretation of the data contained herein, and makes no representations or warranties of any kind concerning the quality, safety, or suitability of the information, whether express or implied, including, without limitation, any implied warranties of merchantability or fitness for a particular purpose.