Cloudy Pool Water? Here’s Why & How To Clear It
Having a cloudy pool isn’t just unsightly, it can also be dangerous. Cloudy water is usually the result of low sanitization levels, which can lead to bacteria and algae growth that can even make swimmers sick.
Fortunately, there are several steps you can take to better understand and quickly clear up your cloudy pool water – and you’re in the right place to discover them.
This expert guide covers why pool water gets cloudy, alongside exactly how to clear pool water, so you can get back to your leisure activities in no time – and avoid any potential health problems for your friends and family.
Swimming pool water basics
Balanced pool water is the key to keeping a clean and healthy pool. Your swimming pool water should have an adequate level of chlorine (usually between 1 ppm and 3 ppm) as well as pH stabilisers, calcium levels and other chemicals that are necessary for keeping your pool in good condition.
To get these levels right, you need to test your pool regularly. There are a number of ways to test your pool water. The easiest way to test your water chemistry is with test strips.
For regular testing we’d recommend using a photometer which is a digital pool tester. This works by collecting samples of the water and mixing them with reagents, you’d then use the photometer to read the results. For anyone concerned about the safety of swimmers in the pool this is the most reliable way.
You can also get a manual version of this method of testing, known as a domestic pool tester kit. These are cheaper and more manual options of testing the water using the same tablets and methods as a digital tester. Testing your pool water is essential to avoid any cloudy water problems in the future.
When these levels become unbalanced, they can cause cloudy pool water – so it’s essential that you get them right before attempting to clear up your pool. You should also look into the exact causes of cloudy pool water, as this can help you to avoid the problem in future.
Why pool water gets cloudy
Cloudy pool water is often caused by 4 main types of pool water problems: low chlorine levels, poor filtration, poor water chemistry, or contaminants like debris or algae in the water. These are the main culprits of cloudy water, and often a combination of these issues can cause your pool to become cloudy.
The most common reason for cloudy pool water is a lack of chlorine in the pool, followed by filters, followed by contaminants. 90% of the time it’ll be having the chlorine level too low – in which case you have to dose the pool, maybe add some clarifier if needed and then backwash this away.
Low chlorine levels in the water can also cause algae to grow, which may contribute to a cloudiness of the water (in addition to green or brown discoloration). Poor filtration can also play a role here, as it may mean that the contaminants and particles are not being properly removed from the water.
Finally, poor water chemistry can also cause cloudy pool water. This is because if you have an incorrect pH balance or calcium hardness levels, then the minerals in the water can become suspended, causing a cloudiness.
Important note
At certain times of year, particularly at the start of summer when swimming pools are opening after being closed for winter, your pool may have extremely cloudy water that is difficult to clear.
This is usually caused by high levels of organic contaminants that have built up in the water during the winter, in addition to the system having been inactive for a long period of time. If this is the case, don’t panic – your pool water can still be cleared! We’ll discuss exactly how next.
How to clear cloudy pool water
- Balance PH and free chlorine (FC) levels
While pH levels are not directly associated with pool water cloudiness, they do impact how chlorine and other chemicals work together in your water.
When pH levels are too high, calcium will not dissolve correctly and can cause the pool water to become cloudy or form a scale buildup. Having a high pH level within your water will also cause pool chemicals to be less effective.
This will result in cloudy water that will not be effective for killing bacteria, algae or other microorganisms present in the water.The diagram below shows the extent of how quickly a high pH will decrease the efficiency of sanitiser within the pool water.
If a pH level is too low it means the water is more acidic. This can result in damage to the plant room equipment. The water may also become corrosive, causing staining to the pool. A low pH level may also cause irritation to swimmers, commonly irritating the skin and eyes of people in the water.
To balance this, always aim to keep your pH levels between 7.2-7.6 and free chlorine (FC) within 1-3 ppm. If you’re working with a Bromine system these levels are recommended to be 3-5 ppm.
Expert pool water treatment services will often take care of this, and other chemical treatment and cleaning needs, for you on a regular basis.
Top tip for outdoor pools
Cyanuric acid can be used as a stabiliser for chlorine in swimming pools exposed to sunlight.
It helps to reduce chlorine loss by protecting the free chlorine in the pool from the sun’s ultraviolet rays, maintaining free chlorine levels and reducing the amount of chlorine needed to maintain proper sanitiser levels.
With the proper chlorine concentration, cyanuric acid can also help to reduce the risk of eye and skin irritation. The Cyanuric Acid range is recommended to be 50 to 80 ppm, exceeding this can cause an increased chlorine demand in your pool and also result in cloudy water or scale formation. High levels of cyanuric acid over 150mg/litre should be avoided as it causes chlorine lock.
We’d recommend leaving this step to the specialists – along with most of the technical pool maintenance requirements – to ensure that the job is done properly and safely.
- Get rid of ammonia
Pool chemicals such as chlorine and bromine, when exposed to organic matter in the water, can form ammonia. Ammonia is toxic to swimmers, so it’s important to maintain your pool effectively by clearing it of ammonia regularly.
This can be done by shocking the pool with ammonia clearing solutions from a certified and safe pool store, or investing in ammonia clearing or pool shocking services.
You may also want to consider an ammonia-testing kit, which you can use to test the water regularly and ensure that there are no signs of ammonia present in your pool, but a professional water treatment can also test and diagnose the cause of the ammonia and identify the best solution.
- Monitor and balance Total Alkalinity (TA) levels
It is also essential to closely observe shifts in TA levels. With an elevated TA level, murky water due to pH and calcium scaling is more likely. The ideal TA level is between 80-140 ppm, but this can vary depending on your pool type and size.
If you notice that the TA levels are too high for your specific pool configuration, it’s best to enlist a professional service as they will be able to adjust the TA levels safely without damaging or adversely affecting other chemical readings.
Reducing the total alkalinity of your pool requires first aerating it and then adding muriatic acid, boosting its pH to proper levels. With the help of a pool water treatment, you can rest assured that your pool’s TA levels will be safely and effectively balanced.
- Backwash filter or replace filtering agent
Your pool filter system and pool pump are key components when it comes to avoiding cloudy water.
If your pool is cloudy despite proper maintenance, it may be time to backwash the filter or replace its filtering agent. The timing of this varies depending on the type and size of your filter, but a general rule of thumb is to backwash it once every few weeks.
When replacing the filter agent, be sure to use only products that are safe for your pool type and size. You can find these at certified and reputable pool stores.
Finally, be sure to check the impeller of your swimming pool pump, as a broken part could affect the quality of the water in your pool. If necessary, have it replaced by a professional as soon as possible.
- Correct calcium hardness (CH) levels
Calcium Hardnessis the measure of how hard or soft the water is. The hardness depends on the amount of mineral salts, mainly calcium, that are dissolved in the water. The more salts the harder the water will be. This is also dependent on location. Some areas of Scotland have very fort water in contrast to some areas of Kent that can have very hard water.
The Ideal range for CH (Calcium Hardness) is 200-275ppm. If your CH level is below 200ppm then you can dose the water with some Calcium Hardness Raiser. If the CH level is above 275ppm then we’d recommend dosing with a Scale & Stain Inhibitor. A scale inhibitor works by keeping the minerals in solution, preventing them for being precipitated out and causing scale deposits. These can then be removed easily by the filter.
- Total Dissolved Solids (TDS)
TDS, is the sum of everything that is dissolved in the water including minerals, chemicals and debris. It’s recommended to not let this get above 1,500ppm. The only way to reduce a high TDS is by partially draining/backwashing the pool and replenishing the water with fresh water.
If the TDS of a pool is too high it can cause the pool to look dull and the water may taste salty. It will also cause poor chemical efficiency so regular backwashing and topping up is recommended.
- Eliminate young algae growth
Pool algae growth is often enemy number one after a long winter season. If you don’t want to deal with murky pool water caused by algae, then it’s important to take steps to prevent young algae growth in the first place.
This can be done by keeping your pH levels balanced, keeping chlorine levels at recommended levels and testing them regularly, cleaning the pool walls and floor of dirt and debris that can feed the algae, and adding an algaecide to your pool.
If your pool already has existing algae growth, you’ll need to shock it with chlorine or a non-chlorine shock treatment. This will kill off any existing algae in the pool and help keep your water looking clean and clear.
- Remember deep cleaning
Please remember to keep your pool clean! It is important to routinely rid the pool of any foreign objects or mineral build-up, and perform a thorough scrubbing and vacuuming of the entire surface.
A manual vacuum can do wonders to your pool’s water, particularly if you’ve neglected your maintenance duties for a while. This will help keep your pool free of debris, and give you a better chance at keeping it clean and clear.
If you don’t have the time or energy to do deep cleans yourself, there are plenty of pool services that can perform this task for you. It may be worth investing in a professional cleaning service if you want to ensure your pool stays looking its best.
- Use pool flocculant
Pool flocculant is a chemical you can add to your pool that collects tiny particles in extremely cloudy water, making them large enough for your filter to trap, and thus clearing up the water.
It is important to note that this method should only be used in extreme cases of cloudiness. Once you have added a flocculant, it will form a sludge-like substance at the bottom of your pool that needs to be vacuumed out.
Be sure to read the manufacturer’s instructions and safety warnings carefully before you use pool flocculant, or enlist an expert to support you with this, as it can be dangerous if handled incorrectly.
- Consider automation
Automatic pool sanitisers and dosing systems are a great way to keep your pool looking its best. A dosing system like the Pool Manager helps to keep your pool filter clean and efficient, which can help improve water clarity and circulation.
They are also a great way to save yourself time and energy on manual cleaning tasks. Automatic cleaners can be programmed to cycle through the pool at regular intervals, helping to pick up dirt and debris from the bottom of the pool when you need it.
In addition to cleaning automation, an automated filtration system, automatic backwash and dosing system, or even an ozone system or UV sanitiser can all provide ongoing support with clearing cloudy pool water and ensuring a balanced pool.
Automated pool filters and sanitizers can help reduce the amount of time and energy you spend on regular pool maintenance, while also helping to keep your water clean and clear. Investing in one of these systems may be a great option if you want a low-maintenance solution for keeping your pool water clear.
Avoid cloudy water with adequate pool decommissioning and recommissioning
As we mentioned above, when you open your pool after a period of closure (such as over winter) it can be particularly prone to cloudy water. To avoid this, make sure you properly ‘Summerise’ and ‘Winterise’ your pool – preparing it for the seasons ahead
Jumpstart the season with a pool re-commissioning procedure or Summerise pool maintenance service to ensure that your swimming experience is as safe and productive as possible. This type of service is a must-have to protect against harm resulting from winter weather, like water leaks or corroded parts.
To protect your pool from frost, debris and other damage before and during the winter, you must ensure that it is thoroughly and accurately decommissioned before long periods of inactivity. If left unprepared, sudden temperature drops can cause major damage to it such as fractures, split plumbing and more.
As such, between September and November (depending on your pool heating option), it is recommended that you ensure a pool decommissioning or Winterise pool maintenance service to maintain its condition during the cold winter season.
Closing thoughts
Dealing with cloudy pool water can be a daunting task, but by following these steps and ensuring proper maintenance of your pool, you should have no trouble keeping it looking sparkly and clear.
Always remember to take the necessary safety precautions before attempting any kind of pool service or chemical application. It is also important to use the correct equipment for the job and follow the manufacturer’s instructions carefully when handling any chemicals.
If in doubt, it is always best to enlist the help of a professional pool technician for more complex tasks. At Blue Cube Pools, our expert pool water treatment services are dedicated to helping you keep your pool fresh and functioning, so don’t hesitate to give us a call!
On top of this, our Winterising, Summerising & Ongoing Pool Maintenance Services will help ensure your pool is always in top condition. With quality products and a team of knowledgeable technicians, we can make sure that your dream pool stays dreamy.
Don’t leave your pool cloudy. Contact our pool maintenance specialists today.
Cloudy Pool Water FAQs
Why is my pool water cloudy?
The most common reason for cloudy pool water is a that the chlorine level is too low. There are a range of other factors that can cause your pool water to become cloudy, such as dirt and debris, incorrect water chemistry, or inadequate filtration. It’s also common for pool water to become cloudy after long periods of inactivity, particularly if the pool hasn’t been decommissioned beforehand.
For support in diagnosing and resolving the issue, it is best to enlist the help of a pool maintenance professional.
What does flocculant do to pool water?
When your water is cloudy, a flocculant can be the perfect solution to improve clarity. Flocculant is a clarifying agent that causes dirt and debris to clump together and settle at the bottom of the pool, making them easier to vacuum up. Be sure to follow the manufacturer’s instructions carefully when using a flocculant, as it can be dangerous if handled incorrectly.