The problem of cloudy pool water: It’s Friday afternoon and you just got home from work. It’s hot and you’ve been day-dreaming about your wonderful, relaxing, and cold pool waiting for you. You arrive and, “Oh no!” It’s clouded up with gunk and funk and your relaxing idea just turned into more work!
This happens to all pool owners at one point or another, and while it is always frustrating, thankfully it can be managed and fixed with some simple steps. This article will not only help you clear your cloudy pool back to its pristine, ready for use conditions, but will also help you start a maintenance regimen to avoid it happening in the future!
How To Clear Cloudy Pool Water Fast! [summarized]
We go more in detail further in the article, however, this is how to get rid of the cloudiness in your pool water in a nutshell:
- Test your chemical levels and pH!
- pH should be in a range of 7.2 to 7.8.
- Sanitizer levels should be in-between 1-4ppm for chlorinated pools, and 5ppm for bromine pools.
- Make the necessary adjustments to get levels back within appropriate range.
- If algae is the cause, brush the pool then use an appropriate shock treatment.
- Use a clarifying or flocculant agent.
- Backwash or tear-down and clean your filter, then vacuum the bottom of the pool.
- If cloudiness persists, consider calling a professional service for an assessment as there may be a greater issue than water chemistry imbalance.
Causes of Cloudy Pool Water
First, let’s talk about what causes the cloudiness in your pool.
The most common cause of cloudy water in pools is a chemical imbalance. Often when sanitizers (chlorine, bromine, etc.) run low, it promotes contaminant growth which leads to murky water. Testing at least once a week is a good way to avoid an imbalance reaching the point where water quality is affected and other solutions must be considered.
Another common cause for cloudy water is filtration and circulation problems. A malfunctioning pump-motor, or a poorly maintained or damaged filter can cause a reduction in water-flow in the system allowing for sediment buildup and/or contaminant growth.
Both of the prior stated issues often lead to a biological contaminant (such as bacteria and/or algae) to be able to better propagate in your pool. This can happen surprisingly fast at certain times of the year depending on weather and temperature!
Finally, geographic location of the pool is important as both water hardness and physical contaminants (debris from weather) can build up and affect chemical balances. It’s important to know where a pool is located and what are the common types of debris that fall into it. Excessive debris will make your system have to work harder and require more regular cleaning and maintenance of the filter and pump systems.
Different types of “cloudy”
The most important factor in clearing cloudiness from pool water is determining what the cause is. Observing the color of the contaminated water can potentially tell you what is causing the problem.
For instance, green or yellow cloudiness is almost always due to algae or biological contaminants. White cloudiness can be due to calcium present in the water, or in the case of DE (diatomaceous earth) filter systems, could be indicative of a tear in a grid. Brown or black cloudy water is usually due to dust, dirt, or similar debris falling or being blown into the pool.
How To Clarify Cloudy Pool Water
First, you need to test your levels
The first step to clearing cloudy water in a pool is to determine why it is occurring. Chemical testing is therefore required to solve the problem. Taking any standard pool testing kit, whether in strip form or using liquid reagents, and determining both your pool’s pH as well as sanitizer levels will give you the first clue as to why cloudiness is presenting in the water.
The correct level of pH
Your pH level should be between 7.2 and 7.8.
pH determines whether water is acidic or basic. The ideal range for pool water is between 7.2 and 7.8. Within this range the water is safest for bathing and best at holding chemical additives used for sanitation and maintenance.
Whichever sanitation method you choose to use on your pool, levels must be maintained regularly by adding more amounts of the chemical. Regular testing helps pool owners adjust their chemicals accordingly to avoid low concentrations which lead to algae growth and cloudy water.
This step will be different for those who use chlorine, and those who prefer bromine.
Do you use chlorine?
Your free chlorine levels should read between 1 and 4 parts per million.
In chlorinated pools, levels should read between 1-4ppm (parts per million) of FC (free chlorine) for ideal protection. A lot of different factors contribute to chlorine loss in pools, even the sun! Over time, chlorine breaks down into chloramines because of nitrogen and ammonia present in the water. Bacteria and algae love these compounds and begin to propagate when chlorine levels drop below the threshold of effectiveness.
Chloramines do not provide sanitation, are light, and rise to the water surface to gas off; they are the cause for the common smell associated with chlorinated pools. This is why regular amounts of chlorine must be added to compensate for this. When chlorine levels are not regularly maintained, bacteria, algae, and other biological contaminants can grow and affect the clarity of water in a pool.
Other products such as cyanuric acid are used to help chlorine last longer, which helps protect it from degradation due to UV radiation from the sun. On the other hand, too much CYA (cyanuric acid) can be a problem.
Do you use bromine?
Sanitizer levels in bromine pools should read between 3 and 5 parts per million.
In bromine pools, levels should read between 3-5ppm. Bromine is a common, if more expensive alternative to chlorine for pool sanitation. It has its own advantages and disadvantages and isn’t necessarily better, just suited for different applications.
For instance, there is no way to protect bromine from UV radiation burn-off unlike chlorine, making it less effective in outdoor, uncovered pools. However, because of its much more stable nature, when used in indoor pools or spas, additional application is not needed as often as with chlorinated pools. It’s also more stable at higher temperatures, making it ideal for spas.
Like chlorine, over time bromine breaks down into compounds called bromamines, however unlike chloramines, these have the advantage that they do not gas off and with the addition of an appropriate shock treatment can be reactivated for further use.
Regardless of your choice for sanitizing agent, regular testing and addition of chemicals is the first step towards avoiding a cloudy pool; but what if it’s too late and has already happened? There are steps you can take to help remedy the situation that are easy and affordable. Learning these steps will be valuable to both you and your pool in the future to avoid these problems.
Shocking the Pool
This practice refers to using a hyper-concentrated dose of chlorine (or alternatives on non-chlorinated systems) on your pool temporarily to break down chloramine as well as destroy any existing algae or bacterial colonies growing in the water. Ironically, shocking a pool can make it even more cloudy, but this is a temporary state as after some time it will clear up.
Shocking a pool is an aggressive action that while necessary every once in a while, should not be relied upon regularly as a solution to pool cloudiness or algae blooms. Read the instructions on the label carefully and make sure to test your water before application to be sure that it will have the desired effect.
When used correctly, this is a very effective way of reducing algae and bacterial blooms that present in your pool, thus allowing for easier maintenance using your normal sanitation solution.
One of the most important bi-annual maintenance tasks you can perform on your pool is the tear-down and cleaning of your filter. This is done by shutting down the entire system, emptying the filter of its water, then opening and removing individual components for cleaning (usually just a spray-down with a hose), or replacing broken parts.
You can read more about how to clean/backwash different filters in our article on the best pool filters.
It shouldn’t surprise anyone that equipment and materials used in pools degrade over time. Water, pressure, chemicals, and environmental factors inevitably lead to part degradation in even the most meticulously maintained pools; this is normal and to be expected. Grids from DE (diatomaceous earth) filters tear over time and must be replaced. Cartridge filters (which look somewhat like air filters on performance vehicles) also degrade over time, albeit more slowly, and must also be cleaned bi-annually to remove all the debris that they effectively catch from the pool throughout the year.
Not unexpectedly, when dealing with a cloudy pool, one of the first and easiest steps you can take to help solve the problem is to do a backwash of your filter (if the assembly allows for it), or a full tear-down. Doing so ensures that any damaged parts can be identified and replaced and filtration can resume more effectively for the system. Often this alone can be very effective at reducing the amount of detritus present in pool water.
After performing a back-wash, a telling sign that the grids of a diatomaceous earth filter are broken is a ton of DE is spit back into the pool from the return-pipe when it is added to the skimmer. While a little bit is normal, if a large amount is pumped back into the pool, then you most likely have to tear-down your filter and replace broken and torn grids. When the filter grids are torn or broken, they are not trapping the debris and contaminants effectively and it inevitably leads to cloudiness in the pool, whether from excess DE or from algae growth.
When adding one time special chemicals like shock treatment to try and eliminate cloudy water due to algae blooms, it’s important to run the motor-pump for longer than the normal daily schedule. This can sometimes go up to a full 24-hour cycle to help the system better filter the added chemicals for more effectiveness.
Clarifying agent to the rescue!
If after these steps your pool is still presenting cloudy or murky water, you can try to remedy it by adding a clarifying agent, a pool flocculant, or both depending on severity. While these chemicals do not sanitize, they help bind compounds present in the water that are causing the problem into bigger, heavier clumps making them easier to be caught by the filter as they pass through the system.
Vacuuming up the debris that will inevitably form at the bottom of the pool will be required after application of these products. Performing a tear-down or backwash is highly recommended after adding a clarifying or flocculant agent as well, as it will cause a substantial rise in debris to form on the filter.
Calcium and Water Hardness
Depending on the water quality available in your area, you might experience calcium scale (also known as limescale) buildup in your pool. This effect is caused by an abundance of calcium present in the water, and apart from creating hard, difficult to remove calcium deposits on surfaces of the pool, can also be a cause for cloudiness in the water!
Aim for calcium hardness of 200 to 400 parts per million.
When testing for calcium hardness, levels should ideally be between 200-400ppm. Low calcium levels can damage pool infrastructure, but high levels lead to scaling and cloudy water.
Unfortunately, the most effective method to combat high calcium in pool water is to perform a partial drain and refill. Once it is present in a pool system, calcium is very hard to eliminate, and most chemical solutions are not very effective compared to a partial drain of the water.
You can also watch the short video below to learn more about calcium in pool water:
Weather such as rain or wind can add debris and phosphates to your pool. Algae love these compounds and thrive whenever they are abundantly present in pool water. It’s important to check your chemical levels after a storm, and take appropriate action according to the readings, topping off whatever sanitizers are low, and adjusting levels accordingly to compensate for the changes in the water.
It’s important to note that all the solutions discussed above can interact and affect one another, so it’s best to try one thing at a time, not all at once! Step by step, testing, adjusting, testing again, cleaning, and testing once more can help avoid interactions in these chemical products that could exacerbate the situation and possibly make it worse!
Clearing cloudiness from pool water requires patience and participation to solve, as there are so many reasons why it can occur. If after all these steps (and maybe a few others), you still cannot find a solution to the problem, calling a professional pool service to come and make an evaluation might be a good idea.
Many services won’t charge for a first-time assessment, and may even be willing to offer advice on what other products or work can be done to offset the problem! There’s always a solution, sometimes it can just be a bit more difficult to find!