Step-by-Step Instructions for Testing and Balancing Your Pool Water

You can learn how to: test and balance your pool water with a good test kit. Check each important level and add the right pool chemicals to keep the water safe and clear. Test your pool water often to protect swimmers from germs and skin problems. Aquachem is a trusted company that provides high-quality products for your pool.

Balanced water lets you swim in clean, shiny water every time.

Key Takeaways

• Test your pool water often to keep it clean and safe. Try to test it two or three times each week when you swim a lot.

• Keep the pH level between 7.2 and 7.6. This helps protect swimmers and makes sanitizers work well.

• Check alkalinity often. Keep it between 80 and 120 ppm. This helps keep pH steady and stops water problems.

• Watch calcium hardness and keep it from 200 to 400 ppm. Balanced calcium keeps pool surfaces and tools safe.

• Use enough sanitizer, like chlorine or bromine, to kill germs. For chlorine, keep it between 1.0 and 3.0 ppm.

• Add cyanuric acid to help chlorine last longer in sunlight. Keep cyanuric acid between 30 and 50 ppm for best results.

• Follow each step to test and balance your pool water. This makes swimming safe and fun for everyone.

• Store pool chemicals in a safe place and read all labels. Good storage stops accidents and keeps your family safe.

Why Pool Water Testing Matters

Health and Safety

You want your pool to be a safe place for everyone. Pool water testing helps you spot problems before they can harm swimmers. When you do not check your water, you risk exposing people to germs and chemicals that can make them sick. Some of the most common health risks include:

• Chlorine poisoning from too much chlorine in the water or air.

• Breathing problems caused by chlorine gas, especially in indoor pools with poor ventilation.

• Accidental swallowing of pool water, which can be dangerous for children.

• Uneven chlorine levels from poor maintenance, leading to unsafe swimming conditions.

• High temperatures can make chlorine problems worse.

You use pool water chemicals to kill germs and keep the water clean. If you do not use the right amount, you can create new risks. Chlorine is the most common chemical in pools, so you must handle it with care. Regular water testing helps you keep chemical levels safe and balanced.

Aquachem cares about your safety. The company designs its products to help you protect your family and friends every time they swim.

Protecting Pool Equipment

Pool water testing does more than keep swimmers safe. It also protects your pool equipment. When you let the water get too acidic or too alkaline, you can damage your pool’s parts. Problems you might see include:

• Corroded pool heaters and metal ladders.

• Calcium buildup inside pipes and filters.

• Rusted or stained pool surfaces.

These problems often start small. You may not notice them right away. Over time, they can lead to expensive repairs or even the need to replace equipment. Using the right pool water chemicals and testing your water often helps you avoid these issues.

Aquachem’s pool water chemicals help you keep your pool equipment in good shape. The company’s products work to balance your water and prevent damage.

Saving Time and Money

When you test your pool water regularly, you save both time and money. Small problems are easier to fix than big ones. If you wait too long, you might need to spend more on repairs or extra chemicals. Pool water testing lets you catch issues early, so you can act fast.

You also use fewer pool water chemicals when you keep your water balanced. This means you spend less money over the swimming season. Aquachem’s products make it simple to keep your pool clear and safe, so you can enjoy swimming without worry.

Tip: Make pool water testing part of your weekly routine. You will keep your pool sparkling and avoid costly surprises.

Key Water Parameters

To keep your pool water balanced, you must check a few things. Each one helps make your pool safe, clear, and nice to swim in. These are the key water parameters you should know:

• pH: 7.2 – 7.6

• Alkalinity: 80 – 120 ppm

• Calcium Hardness: 200 – 400 ppm

• Stabilizer (Cyanuric Acid): 40 – 60 ppm

• Free Available Chlorine: 1.0 – 3.0 ppm

pH Levels

Ideal Range

Try to keep your pool’s pH from 7.2 to 7.6. This range feels good for swimmers. It also helps your sanitizer do its job. Most experts say 7.4 to 7.6 is best. When pH stays in this range, you protect people and pool equipment.

Effects of Imbalance

If pH is too high, swimmers may get itchy skin or red eyes. High pH also makes chlorine work less well. Germs can stay in the water. If pH is too low, the water turns acidic. Acidic water can eat away at metal parts. Pool walls might get stains or rough spots. You could see faded colors on the pool. Keeping pH balanced stops these problems and helps your pool last longer.

Tip: Aquachem’s pH balancers help you fix pH fast and safely.

Alkalinity

Target Range

Total alkalinity should be between 80 and 120 ppm. Alkalinity helps keep pH steady. If you keep alkalinity in this range, pH will not change quickly.

Role in pH Stability

Alkalinity stops pH from moving up or down too fast. Low alkalinity makes water unstable. You might see cloudy water or rusty spots. Stains can show up too. High alkalinity can push pH too high. Then chlorine does not work as well. You may also see white scale on pool surfaces and equipment. The right alkalinity helps sanitizer work and keeps water clear.

Note: Aquachem has alkalinity buffers to help you keep water steady.

Calcium Hardness

Recommended Levels

Keep calcium hardness between 200 and 400 ppm. This range protects pool surfaces and equipment.

Preventing Scale and Corrosion

Low calcium hardness makes water harsh. It can pull calcium from pool plaster and grout. This causes rough spots and leaks. Metal parts can rust faster. High calcium hardness can cause white scale to form. Scale looks chalky and can cover pool walls and equipment. It can clog filters and make your pool look bad. Balanced calcium hardness stops both rust and scale.

Keep your pool healthy with Aquachem’s water balancers for calcium hardness.

Sanitizer (Chlorine/Bromine)

Proper Levels

Sanitizers help keep your pool water safe from germs. You should check sanitizer levels often to keep the pool clean. Chlorine and bromine are the most common sanitizers for pools. Both kill bacteria and stop algae from growing.

For chlorine, keep the free available chlorine between 1.0 and 3.0 parts per million (ppm). This range helps fight germs and keeps water clear. If chlorine is less than 1.0 ppm, bacteria can grow fast. If it is more than 3.0 ppm, swimmers may smell chlorine or get skin irritation.

Bromine works well in hot tubs and spas because it stays stable in heat. The best bromine level is 3.0 to 5.0 ppm. Bromine is softer on skin and eyes, but you still need to test it often.

Tip: Test sanitizer levels at least two times a week. Do this more after heavy pool use or rain.

Aquachem Sanitizer Products

Aquachem has many sanitizers to keep your pool water safe. You can pick chlorine tablets, granules, or liquid forms. Aquachem’s Trichloroisocyanuric Acid (TCCA) tablets give a slow, steady release of chlorine. These tablets are good for daily use and help keep chlorine levels steady. If you need something fast, Aquachem’s Sodium Dichloroisocyanurate (SDIC) dissolves quickly and raises chlorine levels right away.

For pools that use bromine, Aquachem’s BCDMH tablets mix bromine and chlorine. This mix works well in pools with high pH or warm water. You can trust Aquachem’s sanitizers to keep your pool water clean and safe for everyone.

Cyanuric Acid (Stabilizer)

Ideal Range

Cyanuric acid, also called a stabilizer, protects chlorine from sunlight. You need to keep cyanuric acid in the right range so your sanitizer works well.

• The best range for cyanuric acid is 30 to 50 ppm.

• Too much CYA makes chlorine work less well.

• Too little CYA lets chlorine break down in sunlight.

Test your cyanuric acid level every month. Do this more if you add fresh water to your pool.

Protecting Chlorine

Cyanuric acid acts like sunscreen for your pool’s chlorine. When you add it, it binds to chlorine and shields it from the sun’s rays. This helps chlorine last longer in outdoor pools.

"Cyanuric acid is used in outdoor swimming pools to bind to chlorine for protection against ultraviolet degradation."

If you do not use enough cyanuric acid, sunlight can break down chlorine fast. Your pool may lose sanitizer power in just a few hours on a sunny day. If you use too much, chlorine will not kill germs as well. Keeping cyanuric acid in the right range saves money on chemicals and keeps your pool water safe.

Aquachem has high-quality stabilizer products to help you keep the right balance. With regular testing and the right Aquachem chemicals, you can enjoy clear, safe water all season.

Step-by-Step Guide to Test and Balance Your Pool Water

Learning how to: test and balance your pool water starts with the right steps. This step-by-step guide will help you collect a water sample, use a testing kit, and adjust the pH level. You will use Aquachem products to make pool water testing simple and effective.

Collect Water Sample

Best Practices

You need a good water sample for accurate results. Follow these steps to collect your sample:

1. Select the sampling location. Pick a spot away from return lines, near the deep end or the middle of your pool.

2. Prepare the container. Use a clean plastic bottle that holds 8 to 12 ounces of water. Rinse it with pool water before use.

3. Collect the sample. Hold the bottle upside down and lower it about 18 inches below the surface. Turn it right-side up to fill.

4. Cap the container. Shake off extra water and close the lid right away to keep air out.

5. Test the water immediately. This gives you the most accurate results.

Tip: Always collect your sample at the same spot each time for consistent pool water testing.

Use Pool Water Testing Kit

Types of Kits

You have several options for testing your pool water. Each type has its own strengths.

• Test strips give you a fast overview of your pool’s chemical balance. They work well for routine checks.

• Reagent kits use drops and color changes for more detailed results. They help you make precise adjustments.

• Digital testers are easy to use and provide high accuracy.

Liquid test kits cost more than test strips, but they give you a full picture of your pool’s chemistry. You need to measure carefully for the best results.

Aquachem Test Strips

Aquachem test strips make pool water testing easy. You only need one dip to get all the important results. These strips are accurate and reliable. You can trust them to show if your pool water chemicals are in the right range. Always follow the directions on the bottle for the best results.

Note: Aquachem test strips help you check for impurities and keep your pool safe.

Test pH and Adjust

Using pH Reducers (Aquachem)

After you test the water, you may need to adjust the pH level. If your pH is above 7.6, use Aquachem pH Reducer. This product lowers the pH to the safe range of 7.2 to 7.6. Follow the instructions on the package for the right amount. Using a pH reducer helps improve water clarity and makes swimming more comfortable.

• Add the pH reducer while the pump is running.

• Pour it slowly in front of a return jet for even mixing.

• Wait at least one hour, then retest the water.

This step is important for chemical balancing and balancing pool chemicals. Keeping the pH in range helps your sanitizer work better.

Persistent High pH Solutions

Sometimes, your pool may have a high pH that does not go down easily. Try these expert tips:

• Inspect your fill water. If your tap water has high pH, use a different source if possible.

• Reduce chemical use. Using too many pool water chemicals can raise the pH. Check your chemical usage and adjust as needed.

Aquachem offers solutions for persistent high pH. Their products and support help you maintain the right balance. Regular pool water testing and careful chemical balancing keep your pool safe and clear.

Remember: This step-by-step guide shows you how to: test and balance your pool water for the best swimming experience.

Check and Balance Alkalinity

You need to keep your pool’s alkalinity in the right range. Alkalinity helps your pool water resist sudden changes in pH. When you balance alkalinity, you make it easier to keep your pool safe and comfortable.

Acid Aerate Method

If your pool’s alkalinity is too high, you can use the Acid Aerate Method. This method lowers total alkalinity without dropping pH too much. Here is how you do it:

1. Test your pool water to find the current alkalinity level.

2. Add a pH reducer, like Aquachem’s pH Reducer, to bring the pH down to about 7.0. Always wear gloves and goggles when handling pool chemicals.

3. Turn on your pool pump and any water features, such as jets or fountains. This adds air to the water and helps raise the pH back up without raising alkalinity.

4. Let the pool circulate for several hours. Test the water again.

5. Repeat the process if needed until alkalinity falls between 80 and 120 ppm.

Tip: Lowering alkalinity takes time. Be patient and test often.

Aquachem Alkalinity Buffers

If your pool’s alkalinity is too low, you need to raise it. Low alkalinity can make your pH bounce up and down. You can use Aquachem Alkalinity Buffer to fix this problem. Here is what you do:

• Test your pool water to check the alkalinity.

• Add the recommended amount of Aquachem Alkalinity Buffer. Sprinkle it across the deep end with the pump running.

• Wait at least six hours, then retest the water.

Aquachem’s buffers help you keep alkalinity steady. This makes it easier to balance other pool chemicals.

Measure Calcium Hardness

Calcium hardness shows how much calcium is in your pool water. You want to keep this level between 200 and 400 ppm. If calcium is too low, water can damage your pool surfaces. If it is too high, you may see white scale on tiles and equipment.

Adjust with Aquachem Products

To raise calcium hardness, use Aquachem Calcium Hardness Increaser. Follow these steps:

• Test your pool water for calcium hardness.

• If the level is below 200 ppm, add the right amount of increaser. Spread it evenly around the pool with the pump running.

• Wait for the chemical to dissolve, then retest.

If your calcium hardness is too high, you may need to drain some water and refill the pool. Always test again after adding fresh water. Aquachem’s water balancers help you keep calcium in the safe range.

Note: Balanced calcium hardness protects your pool and keeps water clear.

Test Sanitizer Levels

Sanitizers, like chlorine and bromine, keep your pool water safe. You need to test these levels often. This step-by-step guide shows you how to: test and balance your pool water for the best results.

Chlorine and Bromine Options

You should check sanitizer levels at least twice a week. Use your Aquachem test strips or a liquid test kit. Here is what you look for:

• Chlorine: 1.0 to 3.0 ppm for pools, 3.0 to 5.0 ppm for hot tubs.

• Bromine: 3.0 to 5.0 ppm for pools and spas.

If your sanitizer is too low, add more. If it is too high, let the level drop on its own or use a neutralizer. Always keep pH between 7.0 and 7.8 to help sanitizers work best.

Regular testing protects swimmers from germs and keeps your pool water sparkling.

Aquachem Chlorine Tablets

Aquachem offers chlorine tablets that make it easy to keep your pool safe. These tablets dissolve slowly and give a steady supply of chlorine. Place them in your pool’s skimmer or a floating dispenser. Check the label for the right amount to use for your pool size.

• Aquachem Trichloroisocyanuric Acid (TCCA) tablets work well for daily use.

• For a quick boost, use Aquachem Sodium Dichloroisocyanurate (SDIC) granules.

Aquachem’s chlorine products help you keep your pool water clean and clear. You can trust these products to protect your family and friends every time they swim.

Add Stabilizer

Cyanuric Acid Application

Cyanuric acid is a stabilizer for your pool’s chlorine. It keeps chlorine safe from sunlight. This makes your sanitizer last longer. You must add stabilizer with care. If you do not, you could hurt your pool liner or equipment. Here is how to use cyanuric acid the right way:

• Use a digital scale to measure the stabilizer powder. Always check the instructions for your pool size.

• Turn off the pool pump if you use the skimmer method.

• Mix the stabilizer in a bucket of warm water. Stir until the powder is gone. This stops clumps and keeps your pool liner safe.

• Pour the stabilizer slowly into the skimmer. Or spread it across the pool surface.

• Turn the pool pump back on. Let it run for a few hours. This helps the stabilizer mix everywhere.

• Brush the pool walls and floor. This helps spread the stabilizer.

• Wait 24 to 72 hours before testing the water again.

Tip: Test your cyanuric acid level after adding stabilizer. Keep it between 30 and 50 ppm for the best chlorine protection.

Aquachem has good stabilizer products. They make this job easy and work well. Using Aquachem’s stabilizer helps your chlorine last longer. It keeps your pool safe.

Shock the Pool

Aquachem Shock Treatments

Shocking your pool gets rid of germs and keeps water clear. You should shock your pool often. Do this after lots of swimming, storms, or algae problems. Here is how to use Aquachem shock treatments:

1. Pick the Aquachem shock treatment that fits your pool. Choose based on cloudy water, algae, or lots of swimmers.

2. Put on gloves and safety glasses to protect yourself.

3. Wear old clothes so you do not get bleach stains.

4. Mix the shock in a bucket of warm water. Stir with a wooden stick until it is mixed.

5. Pour the shock solution slowly into the pool. Spread it around the edges.

6. Run the pool pump for a few hours. This helps the shock mix everywhere.

7. Wait until chlorine levels are safe before swimming.

Aquachem’s shock products work fast. They help make water clear again. Shocking often keeps your pool free from germs and waste.

Note: Always follow the directions on the Aquachem shock label for the best results.

Circulate Water

Ensuring Even Distribution

Good water circulation keeps your pool clean and balanced. When you move the water, chemicals mix evenly. This step is important in every pool care guide.

Good circulation spreads chlorine and other sanitizers everywhere. It moves debris to the skimmer and drain. Small particles go through the filter. If circulation slows, chemicals do not mix well. The filter works less. Water gets cloudy, algae grows, and stains can appear.

Run your pool pump for 8 to 12 hours each day. Make sure water moves in all parts of the pool. Brush the walls and floor to help water move in slow spots. Good circulation helps Aquachem chemicals work better. It keeps your pool shiny and clean.

Tip: Add a little colored dye near the return jets. Watch the dye to see if water flows everywhere.

If you follow these steps, your pool water will stay balanced, clear, and safe for everyone.

Troubleshooting Pool Water Issues

Cloudy Water

Causes and Solutions

Cloudy pool water can make swimming less fun and may signal a problem with your pool care routine. You need to know why your water looks cloudy so you can fix it fast. Here are some common causes and what they mean for your pool:

You can solve cloudy water problems by following these steps:

• Run your pool filter for at least 8 hours each day.

• Backwash the filter until the water runs clear.

• Clean the filter with Aquachem Filter Cleaner to remove trapped dirt.

• Test your pool water and adjust pH to stay between 7.2 and 7.6.

• Check chlorine levels and add more if needed.

• Use Aquachem Shock PLUS or Shock Xtra Blue to clear up the water quickly.

Tip: Always check your filter and water balance first when you see cloudy water. Small changes can make a big difference.

Aquachem Clarifiers

Sometimes, tiny particles stay in the water even after you clean the filter. These particles are too small for the filter to catch. You can use Aquachem Super Water Clarifier or Natural Clarifier to help. These products gather small particles into larger clumps. The filter can then remove them easily.

• Add the clarifier as directed on the label.

• Let the pump run to mix the clarifier throughout the pool.

• Watch as your water becomes clear and sparkling again.

Aquachem clarifiers work fast and help you keep your pool looking its best. You can enjoy swimming in clear water every day.

Chemical Smells or Irritation

Addressing Imbalances

You may notice a strong chemical smell when you walk near your pool. Sometimes, your eyes or skin feel irritated after swimming. These signs often mean your pool water has an imbalance. Many people think a strong chlorine smell means too much chlorine. In reality, it usually means your pool does not have enough free chlorine. When chlorine mixes with sweat, oils, and other waste, it forms chloramines. Chloramines cause the sharp smell and can irritate your eyes and skin.

You can fix these problems by following a few simple steps:

1. Test Your Water Regularly
   Use Aquachem test strips or a liquid test kit. Check free chlorine, combined chlorine, pH, and alkalinity. Write down your results each time. This helps you spot changes quickly.

2. Maintain Proper Chlorine Levels
   Keep free chlorine between 1.0 and 3.0 ppm. If you see a strong smell or feel irritation, test for combined chlorine. If combined chlorine is above 0.5 ppm, you need to shock your pool.

3. Shock Your Pool
   Use Aquachem shock treatments to break down chloramines. Shocking adds extra chlorine to destroy waste and restore balance. Always follow the directions on the package. Run your pump for several hours after shocking.

4. Balance pH and Alkalinity
   Keep pH between 7.2 and 7.6. Make sure alkalinity stays in the 80–120 ppm range. If pH is too low, water becomes acidic and can irritate skin and eyes. If pH is too high, chlorine works less well, and chloramines build up.

5. Improve Circulation and Filtration
   Run your pool pump for 8–12 hours each day. Clean your filter often. Good circulation helps chemicals mix and removes waste.

Tip: If you smell chemicals or feel irritation, do not add more chlorine right away. Test your water first. The problem may be chloramines, not low chlorine.

Aquachem offers a full range of products to help you fix these issues. Their shock treatments remove chloramines fast. Their pH balancers and test kits make it easy to keep your water safe. You can trust Aquachem to help you enjoy a clean, comfortable pool every day.

Maintenance Tips

Testing Frequency

You need to test your pool water often to keep it safe and clear. Regular testing helps you catch problems before they get worse. During the busy swimming season, you should check your pool water more often. Here are some simple guidelines:

• Test your pool water at least 2–3 times per week during peak swimming season.

• Test again after heavy rain, pool parties, or when you add chemicals.

• Check your sanitizer, pH, and alkalinity each time you test.

Frequent testing helps you spot changes in water quality right away. You can fix small issues before they become big problems. Aquachem test strips make this job quick and easy. You only need a few minutes to get results. If you keep up with testing, you will enjoy clean and safe water all season.

Tip: Set a reminder on your phone or calendar so you never forget to test your pool.

Seasonal Adjustments

Your pool needs different care as the seasons change. In spring and summer, you use your pool more. Warm weather and sunlight can change your water balance quickly. You should test and adjust your pool water more often in these months. Add more sanitizer if you see more swimmers or after storms.

In fall and winter, you may use your pool less. Leaves and debris can fall into the water. You should check your pool cover and clean out leaves often. Lower the water level if you close your pool for winter. Add a winterizing chemical kit from Aquachem to protect your pool during cold months.

Note: Always follow the instructions on Aquachem products for the best results in every season.

Safe Chemical Storage

You must store pool chemicals safely to protect your family and pets. Keep all chemicals in their original containers. Store them in a cool, dry place away from sunlight. Never mix different chemicals together. Some chemicals can react and cause dangerous fumes or fires.

Here are some safety tips for storing pool chemicals:

• Keep chemicals out of reach of children and pets.

• Store liquids below powders and solids to prevent leaks from mixing.

• Use gloves and goggles when handling chemicals.

• Close lids tightly after each use.

Aquachem labels provide clear instructions for safe storage and handling. If you have questions, you can contact Aquachem’s support team. Their after-sales service helps you use and store products safely.

Safety first: Read all labels and follow safety rules every time you handle pool chemicals.

Record Keeping

You need to keep good records of your pool water tests and chemical treatments. Record keeping helps you spot patterns and prevent problems before they start. When you write down your test results, you can see how your pool changes over time. You make smarter decisions about what chemicals to add and when to adjust your routine.

Start by using a simple notebook or a digital spreadsheet. Write the date, time, and location of each water sample. Record the levels for pH, alkalinity, calcium hardness, sanitizer, and stabilizer. Note any chemicals you add and the amount you use. If you shock the pool or treat algae, write that down too.

Tip: Consistent records help you catch small changes before they become big issues.

Here is an example of a pool record table you can use:

You can use a table like this to track your pool’s health. Over time, you will notice trends. For example, you may see pH rise after heavy rain or sanitizer drop after a pool party. You can act quickly to fix problems.

If you use Aquachem products, you get clear instructions for each chemical. The labels show how much to add and when to retest. You can write these details in your records. Aquachem’s support team can help you understand your results and suggest solutions if you have questions.

You should review your records every week. Look for changes in water quality or chemical use. If you see a pattern, adjust your maintenance routine. Good records help you save money and keep your pool safe.

Note: Accurate record keeping makes pool care easier. You avoid guesswork and keep your water balanced.

You can also use pool care apps or online tools to store your records. Some apps let you set reminders for testing and chemical additions. You get alerts when it is time to check your pool. This helps you stay on track all season.

Record keeping is a simple habit that gives you peace of mind. You know your pool is safe, clean, and ready for fun. With Aquachem’s products and support, you can manage your pool like a pro.

You now know how to: test and balance your pool water with confidence. Following a step-by-step guide helps you keep your pool safe, clear, and ready for fun. When you use Aquachem products, you make pool care simple and effective. Regular care shows you how to: test and balance your pool water the right way. For more tips and trusted products, visit Aquachem’s website.

FAQ

How often should you test your pool water?

You should test your pool water at least two or three times each week. Test more often after heavy rain, pool parties, or when you add chemicals.

What is the best way to add pool chemicals?

Always read the label first. Add chemicals while the pump runs. Pour slowly near a return jet. Wait for the chemical to mix before retesting.

Why does your pool water turn cloudy?

Cloudy water can mean your filter needs cleaning, your pH is too high, or your chlorine is too low. Test your water and clean your filter to fix it.

Can you swim right after shocking your pool?

No, you should wait until chlorine levels drop to a safe range. Test the water and make sure chlorine is between 1.0 and 3.0 ppm before swimming.

What should you do if your pH stays high?

Try using Aquachem pH Reducer. If pH does not drop, check your alkalinity and use the Acid Aerate Method. Test again after each step.

How do you store pool chemicals safely?

Store chemicals in a cool, dry place. Keep them in original containers. Make sure children and pets cannot reach them. Never mix different chemicals.

What is the purpose of cyanuric acid in your pool?

Cyanuric acid protects chlorine from sunlight. It helps chlorine last longer in outdoor pools. Keep cyanuric acid between 30 and 50 ppm for best results.

Which Aquachem product should you use for algae?

Use Aquachem Algaecide to kill and prevent algae. Follow the instructions on the label. Brush the pool walls and run the pump for even mixing.