Content

• Steps
• Method 1 of 3: Killing Green Algae with Chlorine
• Method 2 of 3: Other Ways to Get Rid of Green Algae
• Method 3 of 3: Preventing Algae
• Tips
• Warnings

Green water and floating algae are common pool problems. If algae appears in your pool, you will need to purchase various chemicals and take a few days to get rid of them. It is much easier to prevent the growth of algae by regularly maintaining the pool.

Steps

Method 1 of 3: Killing Green Algae with Chlorine

1. 1 Use chlorine as an effective algae treatment. If the water in your pool turns green or there are lumps of algae, then there is not enough chlorine in it. Shocking a pool with a high dose of chlorine is the most effective way to kill new algae and restore water to normal. This usually takes 1-3 days, although it can take a whole week if the pool is heavily overgrown.
   • The other methods listed below give faster results, but they may not solve basic sanitation problems. In addition, these methods are more expensive and can cause unwanted side effects.
2. 2 Brush the walls and bottom of the pool. Scrub the pool surface well to remove as much algae as possible. This will reduce the time it takes to kill the algae. Pay special attention to steps, walls behind stairs, and other nooks and crannies where algae often gathers.
   • Make sure the brush is suitable for your pool. Wire brushes are good for concrete, but nylon brushes are better for vinyl pools.
3. 3 Read the chemical safety rules. In this method, you have to deal with hazardous chemicals. Be sure to read the safety information on the product labels before cleaning your pool. When using pool cleaners, at least observe the following safety precautions:
   • Wear gloves, goggles, and closed clothing. After cleaning the pool, wash your hands and check to see if any cleaning agents get on your clothes.
   • Do not inhale chemical vapors. Be careful in windy conditions.
   • Always add chemicals to water, not vice versa. Do not put wet scoops and spoons back into the container with the cleaning agent.
   • Store cleaning products in sealed, fireproof containers out of the reach of children. Place them on separate shelves, located on the same level, and not on top of each other. Many pool cleaners can explode on contact with other chemicals.
4. 4 Adjust the pH level in the pool. Measure the pH of your water with a pool pH kit. If the pH is higher than 7.6, which often happens with algae blooms, add a pH lowering agent (such as sodium bisulfate) to the water as directed on the package. Keep the pH in the range of 7.2-7.6 - in this case the chlorine will work more effectively, which will reduce algae growth. Wait at least two hours, then check the pH level again.
   • Test kits that use tablets or pipettes are much more accurate than paper test strips.
   • If the pH is back to normal but the total alkalinity is above 120 ppm, refer to the instructions that came with the pH lowering product to find out how to reduce the total alkalinity to 80-120 ppm.
5. 5 Choose a pool shock chlorinator. The chlorine you regularly add to your pool may not be the best way to quickly purify water. It is best to use a liquid chlorine product specifically made for swimming pools. This product must contain sodium, calcium or lithium hypochlorite.
   • Do not use a calcium hypochlorite product if you have hard water.
   • All products containing hypochlorite are flammable and explosive. Lithium hypochlorite is less dangerous, but the products with it are more expensive.
   • Do not use granular or tablet chlorine products (such as dichlor and trichlor) as they contain stabilizers that should not be added to the pool in large quantities.
6. 6 Add generously to the water. Check the instructions provided for how much is required for a typical "shock chlorination" and use twice the amount to kill the algae. Use a triple amount if the water is very cloudy, or even a quadruple amount if the top rung of the ladder is not visible. With the filter on, add the product to the water around the pool. If the pool is covered with vinyl, first fill a bucket with pool water and fill it with cleaning agent to avoid bleaching.
   • A warning: Liquid chlorinating agent will explode on contact with chlorine tablets or granules, producing corrosive gas. Never pour chlorine liquid into the skimmer or other parts of the pool that contain chlorine tablets or granules.
   • Chlorine is decomposed by ultraviolet rays, so it is best to add it in the evening and leave it overnight.
7. 7 Check the water the next day. After the pool filter has run for 12-24 hours, check the water. Dead algae turn white or gray and float in the water or sink to the bottom. Regardless of whether the algae is dead or not, check the chlorine content and pH level again.
   • If the chlorine concentration is quite high (2–5 ppm), but there is still live algae in the water, maintain that chlorine level for several days.
   • If the chlorine content has increased, but does not exceed 2 ppm, repeat shock chlorination in the evening.
   • If the chlorine level has not changed much, there is probably too much cyanuric acid in the water (over 50 ppm). This is due to the influence of chlorine in the form of granules or tablets, which can block the action of the cleaning agent. In this case, you will have to carry out shock chlorination again (sometimes you have to do it many times) or partially drain the water from the pool.
   • Fallen leaves and other objects in the pool can also reduce the effectiveness of the chlorine cleaner. If the pool has not been used for a long time, several shocks may be required and cleaning may take an entire week.
8. 8 Brush the pool daily and test the water. Scrub the pool walls thoroughly with a brush to remove new algae. Over the next few days, the chlorine should kill the algae. Test the water every day to make sure it has acceptable chlorine and pH levels.
   • It is recommended to maintain approximately the following composition of the pool water: free chlorine - 2-4 ppm, pH - 7.2-7.6, alkalinity - 80-120 ppm, calcium hardness - 200-400 ppm. The standards vary slightly, so slight deviations from these values ​​are acceptable.
9. 9 Vacuum up dead algae. After the water has lost its green tint, vacuum up any dead algae to clean the pool. You can skip this step and wait until the filter cope with water purification, but this is only suitable if you have a powerful filter and are ready to wait several days.
   • If you find it difficult to purify the water, add a coagulant or flocculant to the pool to bring the algae together. These products can be purchased at a pool store, but are not always worth buying for your home pool.
10. 10 Clean the filter. If you have a diatomaceous filter, backwash. If there is a cartridge filter in the pool, remove it and rinse with water from a hose under high pressure, and then, if necessary, with diluted hydrochloric acid or liquid chlorine.If the filter is not cleaned properly, dead algae can clog the filter.

Method 2 of 3: Other Ways to Get Rid of Green Algae

1. 1 Improve water circulation to deal with some algae. If there are isolated clumps of algae that do not spread to the entire basin, this may be due to areas of stagnant water. Check the pipes that supply water to the pool. They should be directed at an angle so that the water moves in a spiral.
2. 2 Collect the algae with a flocculant. Under the influence of a flocculant or coagulant, algae stick together, which allows them to be removed with a vacuum cleaner. While this challenging job can take an entire day, you end up cleaning up your pool as a result. This is the fastest way to clean the pool, however after such treatment in it unsafe bathe. If algae appears in the pool, viruses and bacteria can multiply in it. After that, do shock chlorination to disinfect the water, and do not swim in the pool until the chlorine and pH levels are restored to normal.
3. 3 Treat the water with algicide. The algicide will most likely kill the algae, but the side effects and costs may outweigh the benefits of this treatment. In this case, the following factors should be taken into account:
   • Some algaecides are not strong enough to get rid of blooms, especially if there are black algae in the pool. Ask a store employee to help you choose a product or look for an algicide with at least 30% active ingredients.
   • Quaternary ammonium algaecides are inexpensive but foamy. Many people don't like it.
   • Copper-based algicides are more effective but more expensive. They also tend to stain pool walls.
   • After adding algicide, wait at least 24 hours before using other products.

Method 3 of 3: Preventing Algae

1. 1 Monitor the condition of the pool water. With the correct chemical composition of water, algae should not grow in it. Check the free chlorine, alkali, cyanuric acid and pH levels regularly. The sooner you spot a problem, the easier it will be for you to fix it.
   • It is best to test the water every day, especially within 1–2 weeks after the algae bloom. Check the condition of the water at least twice a week during the swimming season.
2. 2 Add algicide as a preventive measure. Algicides are best added in small doses once a week after the water has returned to normal. This will destroy the algae population before they have time to multiply. Review the instructions supplied with the algicide.
   • Follow instructions to prevent, not destroy, existing algae. Too much algicide can stain the pool or cause foam to form.
3. 3 Remove phosphates. Algae feed on various substances present in the water, especially phosphates. The phosphate content of a pool can be measured with a fairly cheap test kit. If phosphates are present in the water, use a standard remover available from a pool supply store. The phosphate can then be removed within 1–2 days using a filter, automatic or hand-held vacuum cleaner. When phosphate levels are normal, do shock chlorination.
   • There is no consensus among experts about the acceptable level of phosphate. 300ppm is probably a fairly low level unless you have persistent algae problems.

Tips

• Heat and sunlight break down chlorine and promote rapid algae growth. Monitor chlorine levels in hot, sunny weather.
• For the winter, purchase a mesh pool cover to keep out debris without blocking water.
• Closely monitor the pool filtration system while cleaning. Thoroughly flush or clean the filter each time the pressure rises 0.7 atmospheres above normal operating pressure. Dead algae accumulated in the filter can quickly contaminate the filter, so the filter must be cleaned frequently.
• If you have time, add ½ of the recommended amount of pool cleaner, then refill the rest as needed after a few hours. In this case, you do not use too much tool and you can always add it.

Warnings

• Do not use the pool until the algae has disappeared and the chlorine level has dropped below 4 ppm.