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Why is my pool so cloudy? How to clear a cloudy pool

One day your pool is crystal clear, pleasant to stare into and almost overnight, it all goes south. Your pool now looks more or less like a cattle dip; cloudy or milky in appearance. You can swear to having impeccable cleaning routines but the cloudy water simply lacks explanation. Don’t despair, cloudy pools are a fairly common occurrence whose cause has often nothing to do with your pool cleaning regimen.


There’s nothing appealing about a cloudy pool. And the worst part? No way you can convince any uninformed person that the milky water isn’t actually dirty, per say. There are numerous factors that lead to cloudy pool water. Your pool’ssurroundings can often cause your water to get cloudy despite regular cleaning. Before embarking on a mission to clear out the cloudy water, it is important to first and foremost establish the root cause of the cloudy pool waters. This article is aimed at exploring the possible culprits behind your pool’s milky appearance and the possible ways to remedy and alleviate this problem.

Why is my pool so cloudy? How to clear a cloudy pool

What causes cloudy pools?

Pool water can become milky when a large concentration of micro particles of matter are introduced intothe water. Alternatively, particles may fall out of solution but remain suspended in the pool water. These said micro particles reflect light causing thecloudy appearance in your swimming pool. The particles come from various sources which might include:

  • Cosmetic products such as sun screen lotions, skin protein emulsions and oils, perspiration and lastly my least favorite; body fluids.
  • Chemical additives and adulterants such as calcium carbonate and various hypochlorite compounds. Acidity and alkalinity levels arecommon causes of pool water cloudiness. Above the 7.8 pH mark,pool wateris not able to hold calcium carbonate in solution. The Calcium carbonate is re-suspended and floats around freely giving the pool water a milky hue.
  • Your pool’s filtration system: Quite often swimming pools are cloudy simply because of insufficient filtration. How many hours of filtration you run per daycan have a significant impact on whether or not your pool is going to get cloudy and by what extent. If the filtration pump isn’t running enough time, chances are that it isn’t going to filter the pool water appropriately. Also, if the pump size is too small for your pool, the net effect can often be cloudy and unappealing pool water. On the same, if your filtration pump has a larger than necessary horsepower range that exceeds your pool size’s needs, the overall effect on the pool water will be similar as in the case of an underpowered motor. The reason behind this is simple; the pool water will be drawn in too fast through the filter reducing effective filtration. The outcome? Cloudy pool water.
  • Plant sources such as pollen, algae, mold spores, dust and superfine sand. Higher pH values cause chlorine to lose potency to repel bacteria and algae. This causes the pool water to become milky. High pH of pool water can be as a result of the overuse of granular Calcium Hypochlorite for shock treatment.

The above particles are extremely small in size varying anywhere between 0.5 to 5.0 microns. On average grain of sand is about 1,000 microns. Most pool filter systems aren’t deigned to deal with any particle size below 30 microns, the above mentioned particles are therefore too small to get caught by your pool’s filtration system.

The aforementioned particles arealso negatively charged. This means that the particles repel thanks to the negative electrical charge. Each particle maintains an isolated suspension state in the pool water. The knowledge of this is important for one major reason; some pool treatment methods involve changing the particles in your pool water’s electrical charge. This causes the particles to attract and stick together forming large coagulates that are easy on your pool’s filtration system.

Why is my pool so cloudy? How to clear a cloudy pool

Cause identified, what next?

Having identified what’s causing the cloudiness the next step is to find a suitable remedy. The good news is that, for the most part, fixing cloudy pools is a fairly simple affair. Before commencing clarification, you need to ask yourself one question; how cloudy is your pool?

There are varying degrees of pool cloudiness. The degree of cloudiness is often an important clue to the root cause which consequently helps you determine the appropriate clarification treatment. Your pool could have lost its sparkle and shine but not by noticeable degree or, the pool water isn’t clear but the bottom of the pool is visible and finally, the visibility could be terribleat the deep end.

For hazy water

Adjust the pH of your pool water to range between 7.2 and 7.6. This range is considered slightly acidic or perhaps even neutral your pool size.Start the filtration pump and leave it running for at least 12 hours.The pool should be crystal clear when it’s all done. For Hazy water caused by algae, it is advisable to use anti-algae treatment otherwise the haze returns worse than before.

Why is my pool so cloudy? How to clear a cloudy pool

Visibly cloudy pool water

Allow the pump to run for about 8 to 10 hours.Afterwards adjust the pH value of the pool water to between 7.2 and 7.6. Run the pump for an extra 4 hours. If the suspected cause of the cloudy water is algae, by all means use anti-algae treatment.

Opaque water line

First, adjust the pH value of your pool water to 7.8.If your pool’s filtration system has a sand filter, proceed to set it on recirculate. In the case of a pool cartridge filter, simply remove the cartridge.Start the filtration pump and leave it runningfor 10 to 12 hours. Afterwards, perform a vacuuming exercise after which you should start the pump and keep it running for 2 3 hours. Wait an additional 24 hours and repeat vacuuming exercise and run the pump to eliminate the waste.

Why is my pool so cloudy? How to clear a cloudy pool


It is recommended to use pool water clarifier products at least weekly. Pool clarifiers work by gathering the tiny particles making your pool water cloudy coagulating them together creating larger particles. Your pool filter will have a better chance of picking cleaning up the coagulated masses afterwards.

I sincerely hope that you have found this article enlightening. Feel free to share your thoughts, comments and suggestions in the space provided below. Share and spread the word on what’s causing cloudy pools everywhere and what can be done.