4 Ways to Clear Cloudy Swimming Pool Water
Cloudy Pool Water: Causes, Treatment, and Preventive Measures
Maybe you have a pool party tomorrow and you suddenly realize that your water is cloudy. Below, you'll find the causes of cloudy water and how to resolve each problem.
Most pools become cloudy...
- because free chlorine has become depleted after heavy usage,
- after heavy rainfall dilutes the cholorine,
- or during a hot sunny days due to UV light eating up free chlorine.
In other words, if the water is cloudy as a result of low free chlorine levels, don't waste time. You need to shock your pool now!
On the other hand, if you are not certain of the cause of cloudiness, this article is for you. You'll need to troubleshoot to find the cause. It could be one of four things:
- Improper or imbalanced chemicals,
- Faulty filter,
- Poor water circulation, or
- Environmental factors and debris (particles).
Read on to find out how to diagnose the problem and what to do to clear it up.
Note: These instructions are for a chlorinated pool. Here are the instructions for clearing a cloudy saltwater pool.
Wrong or Imbalanced Pool Chemicals
Swimming pool chemistry is the most tricky part of pool management. Using the wrong chemicals or adding incorrect amounts are the major causes of cloudy water, and may even lead to having algae if extra care is not taken.
- Improper pH and chlorine levels are the most common culprit: The pH is not directly associated with cloudiness in the water, but it consumes and renders free chlorine ineffective when it's not in balance. And when free chlorine level goes down, it forms combined chlorine (chloramine), which turns the water cloudy and is even ineffective in killing bacteria and other organisms such as algae.
- You also need to closely monitor changes in the level of total alkalinity (TA). A high TA causes a number of problems, including pH and calcium scaling, both of which are associated with cloudiness: Here is how to lower total alkalinity when it gets out of the recommended range - the process involves aeration to raise the pH to recommended level after adding muriatic acid.
- High levels of accumulated phosphate and bromine and imbalanced stabilizers such as a cyanuric acid (CYA) might also cause cloudiness. If you are using cyanuric acid often, make sure that the CYA and free chlorine levels are balanced, since excess CYA will significantly reduce free chlorine. Use this chlorine/CYA chart to determine proper levels.
In order to verify which of these chemicals might be imbalanced, you need an accurate, fast, and easy-to-use test kit. I use digital water test kit. It saves me lots of time as it is easy to use and very effective for frequent use. It tests pH, free chlorine, combined chlorine, total chlorine, bromine, calcium hardness, total alkalinity, and cyanuric acid all at a glance. LaMotte 2056 ColorQ Pro 7
I use a pool calculator to find the exact amount of each chemical to add.
How to Clear Cloudy Pool Water Caused by a Chlorine Imbalance
Ideally, the recommended chlorine levels should be around 3 ppm, which should be the same as the total chlorine if chloramine is at 0 ppm.
The wider the range between free and total chlorine, the more combined chlorine (chloramine) is present in the water.
Combined chlorine should always read below 0.5 ppm or just 0 ppm if possible. This means you need to be testing chlorine levels on a daily basis and adjusting it as appropriate before there's excess chloramine.
If you have an outdoor pool, you can use chlorine stabilizer such as cyanuric acid to prevent chlorine depletion as a result of direct UV light. Remember that cyanuric acid is very strong and if it exceeds the recommended levels, free chlorine will be eaten up and leave the water cloudy and at a high risk of growing algae.
In any case, if combined chlorine reads above 0.5 ppm, your water may turn cloudy and become unsafe for swimming. If this is the case, you need to shock your pool immediately.
Monitoring pH and Total Alkalinity
The concentration of pH in the water affects how all the water's chemicals function, including chlorine. When pH level gets too high, chlorine will become ineffective, and we all know how important chlorine is in a pool.
The correct level of pH in a swimming pool should be between 7.4 and 7.8, with 7.6 as an ideal level.
To lower pH level, you need to use a pH reducer (pH minus) such as muriatic acid or sulfuric acid.
Anything below pH of 7.0 is too low, and apart from turning water cloudy, brings about harmful bacteria such as algae. To control low pH levels, you need to use a (pH plus) with soda ash. pH Increaser
Finally, ensure that total alkalinity is within the required range of 80 ppm and 120 ppm to avoid bringing up pH levels and causing calcium scaling. This article describes the proper way to lower total alkalinity without extra equipment.
Which tool do you use to measure and control your pool chemistry?
When Chemicals Are Balanced but Pool Water Is Still Cloudy
When all the chemicals are well balanced but your water is still cloudy, there is a good chance that you have particles in your pool.
Alternatively, you can use pool floc (flocculant), also known as a super floc, which is a chemical that is used to bring all the clouding particles to the bottom of your pool forming a large cloud which you can then vacuum up using a manual pump. The particles collected using a pool floc will not pass through the filter as they would if a water clarifier were used. Remember to make sure that your filter is set on the 'Backwash' or 'Waste' option when you are vacuuming to avoid any damage that may happen to the filter as a result of clogging.
What If the Swimming Pool Water Is Still Cloudy After Shocking?
In most cases, your water may still look cloudy or milky white after shocking your pool: This is normal and you shouldn't worry. The water will clear up soon, just make sure that your pump and filter are running properly and give it a day.
If the cloudiness persists 24 hours after shocking, it could be possible that you used a poor quality chlorine shock. In this case, you should take the reading of free chlorine and do the shocking all over again using a higher quality chlorine shock.
You should also check that all chemicals—especially pH, total alkalinity, cyanuric acid, and calcium hardness—are within the recommended levels.
Finally, debris could be present in your pool causing continued cloudiness in the water. You can try using a water clarifier to send all particles to the filter, or you can use pool floc and then vacuum using a manual pool pump.
Cloudy Water After Opening a Pool
Depending on how carefully you closed the pool for the winter, at the beginning of summer there may be a problem of algae and cloudy water.
The main cause is chemicals. If your water is free of algae, all you need to do is to test for all the chemicals and adjust, starting with the pH, then chlorine, and other chemicals after that.
If the water still appears cloudy after adjusting all the chemicals, you can try using either water clarifier to remove the debris through the filter or pool flocculant and then vacuum to remove any particles.
Pool Filtration and Circulation Systems
Poor water circulation system can also be a big problem. If your water cannot circulate properly, it will become stagnant and cloudy.
- Ensure that the return fittings (eyeball fittings) are turned to point down enough to enable the water at the bottom of the pool to circulate properly. However, the circulation system will largely depend on how the pool was built.
- Also, ensure that you are using the right pump size to adequately clean the water.
- Make sure the filtration system is running enough. A filter should run 24/7 for the water to remain clean all the time. However, for home pools that are not busy, at least 8 -10 hours a day might suffice.
- Remove particles that may be blocking your filter. Your filter system continuously cleans the water, and if it does not function properly, the water becomes dirty, cloudy, and may even develop algae. Large particles are fond of blocking filtration systems, especially the diatomaceous earth (D.E) and cartridge pool filters.
- Ensure that you regularly clean, backwash, or replace the D.E and cartridge filter medium as appropriate.
Which Pool Filter Is Best?
There are three types of filters: DE (diatomaceous earth), cartridge (paper), and sand. Each has its own pros and cons.
- A DE pool filter is the most efficient when it comes to filtration, followed by cartridge and sand filters respectively.
- On the other hand, DE and cartridge filters are recommended for home pools and may not be the best when it comes to public (apartments or hotels) pools due to their tendency to clog and require frequent replacement of filter medium.
- A sand filter is always best when it comes to public or semi-public swimming pools, but the sand used in a sand filter also gets clogged and becomes ineffective, which may cause your water to be cloudy or dirty. Consequently, the sand should be replaced every year.
Here is a detailed guide on types of pool filters, how to select the best one, and how to properly maintain it.
The Environment Around the Pool and Foreign Particles
The environment and weather may also be the cause of cloudy water.
- Free chlorine depletes more quickly in full sunlight, but if trees and buildings are next to your pool, direct sun will be blocked.
- Rain also has an affect. All you have to do is test all chemicals, especially chlorine, and adjust them as appropriate.
- Large and small foreign particles may find their way into the water, especially during spring. Also, body oil used by swimmers accumulate in the pool in most cases causing cloudiness. You can use nets to remove visible particles or simply use clarifier or pool flocculant and vacuum to do away with fine particles and oily substance.
- In early growth stages, algae also causes cloudiness. Control the amounts of pH, chlorine, TA, phosphate, and other pool sanitizers.