After a summer of enjoying your pool, you decide it’s time to clean the water and start fresh. You dump your favorite brand of chlorine cleaner into your pool, but when you check on it in the morning, you are shocked to discover that the pool is still cloudy and looks dirty.
The high level of chlorine applied to the water during shock is the most likely reason you have a cloudy pool. Although this process eliminates contamination, it decreases the pH level of your pool, resulting in cloudy water. This is a normal reaction that should not be cause for concern.
What is a ‘Cloudy Pool’?
Cloudy pools can look different based on what the cause is and how extreme the chemical imbalance is. Cloudy water can range anywhere from a light, foggy tint to a deep, milky white color. It is important that you identify what degree your cloudy pool is so you can understand the severity of the imbalance.
- Dull: If your pool has a slightly clouded look, this could mean your chemical imbalance is minimal or that the shock treatment just hasn’t had enough time to develop in your water.
- Hazy: If your pool water is a hazy color, this is a sign that your pool is likely chemically imbalanced or dirty.
- Cloudy: If your pool is cloudy and it is difficult to see the bottom of the pool, then you certainly have a chemical imbalance in your pool. You will want to run tests and treat the pool right away.
- Opaque: If your pool is a milky white, green, or gray color, you have an extreme imbalance in chemicals. This could be due to putting in the wrong chemicals or an algae infestation.
What is pool shock?
Pool shock is the process of adding chemicals to your pool to clean your water and destroy contaminates. Usually, the shocking process uses chlorine, but non-chlorine chemical options do exist.
When done correctly, shocking your pool will get rid of unwanted algae, bacteria, and combined chlorine (also known as chloramines). Shocking should be a regular part of your pool upkeep and is a necessary part of keeping your pool safe and beautiful.
When is the right time to shock a pool?
If your pool has any signs of algae or looks particularly cloudy, you should shock your pool right away. It is also a good idea to shock your pool after any high-traffic events you may be hosting, like a pool party.
Days that are extra sunny or extra stormy can interfere with the chemistry of your water, so it’s a good idea to shock on these days also. It is also always necessary to shock before the opening day of your pool and after the closing day. Keeping up a regular shocking schedule will only benefit your pool and keep your water cleaner.
If you are using chlorine, you should always be shocking your pool in the evening after the sun is down. UV rays from the sun can interfere with the process and reduce the free chlorine levels.
What’s the Difference Between Free Chlorine, Combined Chlorine, and Total Chlorine?
There are three types of chlorine, and it is important to understand the difference between them so you can add the right amount of each to your pool. Free chlorine is chlorine before it interacts with chlorinated water.
This is an important type of chlorine because it is extremely potent and is what will disinfect your pool the best. Combined chlorine describes chlorine that has been combined with your pool water and is unable to effectively sanitize.
If there is too much-combined chlorine in your pool, you will get a nasty smell, and you will need to shock your pool. Total chlorine refers to the sum of all chlorine in your pool. It is important to know the total amount of chlorine in your pool so you can avoid a chemical imbalance.
Why is chlorine effective for shocking?
Chlorine is the most effective choice for shocking your pool because it does the best job of disinfecting your water. Chlorine works by breaking apart combined chlorine (or chloramines) which is what causes the bad smell and cloudy water. Using chlorine to shock is the best and quickest way to increase the amount of free chlorine in your pool.
Chlorine is able to get rid of bad bacteria and algae in your pool. Non-chlorinated shock treatments can break apart combined chlorine, but they are not able to eliminate algae or bacteria. Chlorinated shock also has a high pH and can clean the paint and vinyl surfaces in your pool.
Saltwater pool and shock
If you have a saltwater pool, it is also important to shock your pool. Shocking a saltwater pool removes algae, chloramines, and other contaminants in your water. The process is slightly different for shocking a saltwater pool.
When shocking your saltwater pool, you will want to avoid the build-up that can occur when increasing your calcium hardness levels. You will get the best results by using a non-chlorine shock like potassium peroxymonosulfate.
Types of pool shock
There are four main types of pool shock that you can choose between for your pool. The first option is calcium hypochlorite shock, also known as cal hypo.
Cal hypo is one of the oldest and most popular types of shock treatment. To use it, you will dissolve the calcium hypochlorite in water before putting it in your pool.
This shock needs to be used in the evening or nighttime, and it will take about eight hours to complete its job. Calcium hypochlorite shock is 65-75% chlorine and adds 0.8ppm of calcium to your pool.
The second option is lithium hypochlorite shock. This is one of the more expensive pool shock options, but it is also one of the best.
The lithium is fast dissolving, meaning you can dump it straight into your pool in the evening and let it sit for eight hours. This option is great if you have a high calcium content and aren’t concerned about paying a little bit more.
Lithium hypochlorite is also a good algae killer. Because lithium is now used to make batteries, this option is now harder to find in stores and has ceased production at a lot of brands. Lithium hypochlorite shock is 35% chlorine.
The third option is dichloroisocyanuric acid, also known as dichlor shock. Dichlor shock can be used as a shock or as a regular chlorine treatment. This is a decent option for saltwater pools.
Dichlor shock is a fast dissolver and can be poured directly into your pool in the evening to be ready for swimming eight hours later. This is a great option for smaller pools or a saltwater pool with an algae problem. Dichlor shock is 50-60% chlorine and adds 0.9 ppm of cyanuric acid.
The fourth and final option is a non-chlorine shock like potassium monopersulfate. This type of shock will not clean any surfaces in your pool or any algae, but it can be a great quick fix if you need to shock your pool and want to swim in it soon after.
This type of shock improves the function of a saltwater maintenance system while also removing chloramines. You can pour it directly into your pool, and 15 minutes later, it will be ready for swimming.
It is also one of the most affordable options for pool shock. This option is the best option for shocking your saltwater pool if you already have a chlorination system.
How to shock a pool the right way
The first thing you will want to do is go over your pool with a vacuum and use a brush to clean the walls. Once this is done, you’ll need to put on protective clothes, eyewear, and gloves.
Next, test your pool’s pH levels. If everything looks okay, you can prepare the shock treatment by pouring it into a five-gallon container and letting it dissolve into some of your pool water. Some treatments don’t need to be dissolved, so make sure you check your packaging beforehand.
Once your shock is ready, you will want to make sure that your pool’s pump is running and functioning normally. If it is, you can pour your shock treatment into the pool.
Let your pool circulate for around eight hours. After the wait, test your water and see if the chlorine level is between 1-3 ppm. If it is, you are safe to swim.
Different reasons people shock their pools
There are many reasons that people want to shock their pools. Some of these reasonings include the following:
- To remove algae: A chlorine-based shock can also work as a powerful algaecide.
- To remove chloramines: Chloramines smell horrible and can make a pool reek of chemicals. A shock treatment is the best way to get rid of this smell and get rid of your chloramines.
- To remove contaminants: When contaminants get into your pool, they combine with chlorine and become almost impossible to remove. The only way to ensure they are gone is to do a shock with an ample amount of free chlorine.
- To sanitize: If you have recently hosted a pool party, your pool could be full of hair and dead skin. A shock will sanitize your pool and make it clean again.
- To perform general maintenance: Shocking your pool should be a routine part of owning a pool. It keeps your pool clean and your pumps and filters working better.
Reasons why you have a cloudy pool after shock
Seeing that your pool is still cloudy after a shock treatment can be confusing and worrying. There are a few reasons your pool could be reacting this way.
- Filter Problems: If your filter is not properly working, using pool shock will not be enough to remedy the situation. In order to keep your water clear and not cloudy, you will need to make sure your filter is running and working well.
- High level of calcium hardness: Calcium hardness can directly interfere with the success of a pool shock. It is important to know how hard the water is that you are using in your pool. If you are using water that is over 500 ppm of hardness, a calcium hypochlorite shock treatment will make your water even harder. It is important to find the right amount of product to keep your pool’s hardness level between 120ppm and 220ppm.
- High pH level: Finding the right pH balance in your pool is critical, which is why we recommend testing your pH before doing a shock. There are a plethora of things that can go wrong if your pH is wrong, so it is important to know the pH of the shock you are using and test your water beforehand.
- High CYA levels: CYA stands for cyanuric acid. Cyanuric acid is used to stop UV rays from affecting the amount of chlorine in your pool. While cyanuric acid can be a helpful tool to keep chlorine in your pool, you have to be careful to use the right amount, so it doesn’t overwhelm your pool.
- Non-use of pool clarifier: If you do not use a pool clarifier, this is most likely the reason that your pool is still cloudy after shocking. In order to keep your pool safe and healthy, you will need to use a pool clarifier. A pool clarifier binds together particles that are left over after a shock and makes them large enough for your pool’s filter to sift out.
Other causes of Cloudy Pool
- Rainwater: Storms can bring in dirty water and unwanted debris that throw off your pool’s pH balance.
- Sunshine: Harsh sunlight for extended periods of time can remove the amount of free chlorine in your pool.
- Environmental Debris: Things like leaves, grass, sticks, and dirt all carry bacteria that can affect the chemistry of your pool.
- Particles from swimmers: Dead skin, hair, and bacteria all affect your pool.
- Use of more than one chemical: Adding too many chemicals to your pool can overwhelm the water and cause unwanted reactions.
- Algae Buildup: Algae can infect your pool and cloud the water- be sure to check for algae in nooks and crannies.
- Stagnant water: If your pool hasn’t been used for a while on end, the water can still become cloudy and will need to be treated.
- Animals: Pets or wildlife can unknowingly be bringing unwanted bacteria to your pool. It is important to check any hard-to-reach areas and make sure nothing has gotten stuck.
When not to worry about cloudy pool
Sometimes, a cloudy pool after shock is nothing to worry about. The estimated time that it takes for a pool to become clear after a shock varies and can be inconsistent.
If you have waited for the recommended time frame and still see cloudiness in the water, give it an additional eight hours. If after eight hours you still see cloudiness, you may have a problem and should investigate.
Is it safe to swim in a cloudy pool?
Regardless of what the reasoning may be, it is never a good idea to swim in a cloudy pool. A pool being cloudy means that there is an imbalance in the water’s pH, and it is never a good idea to expose yourself to potentially dangerous chemicals or bacteria.
How to clear a cloudy pool (Step-by-Step Guide)
To clear a cloudy pool, you will first want to make sure that all debris is out of the pool. You will then scrub the perimeter of your pool to remove anything stuck to the sides. The fewer algae are caked on, the easier it will be to kill.
Once you have done this, it is time to test the pH balance of your pool. Make sure that everything looks okay; if it doesn’t, evaluate what chemicals you will need to add or subtract from the pool. Knowing the pH balance also helps you determine how much shock you will want to prepare.
After you have made a game plan, add your shock. Let the shock cycle through your filter overnight, and check on it in the morning. If everything looks clear and smells normal, the shock has worked, and your cloudy pool should be fixed.
If it is still cloudy, let your pool sit for an additional eight hours. If, after the additional time, your pool is still cloudy, check your filters, pH levels, and water hardness to find the issue.
How long would it take to clear a cloudy pool?
The amount of time it takes to clear a cloudy pool varies based on what products you use. The typical time frame for clearing your pool should be between 8-12 hours. This is a loose guideline. Some non-chlorine shock treatments only take 15 minutes.
How to prevent cloudy pool
The best way to prevent a cloudy pool is by checking your pH on a regular basis and performing shock treatments often. It is important not to wait until your pool is cloudy or smelly to shock it. Being preventative will make your life easier in the long run.
Checking in on your filters and pumps also helps ensure the clarity of your water. Keep an eye out for unwanted debris and algae that might have made their way into your pool. By paying attention and being proactive, your pool will remain a clean and safe place for your summer activities.
Ruben has a diverse background in the home services industry, with experience running a construction company, a kitchen and bath showroom, and a moving and relocation company. This breadth of experience has provided him with a wealth of knowledge and expertise in various areas of home improvement in general and specifically in the heating and plumbing niche.