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Swimming Pool Water Treatment Tips for Cloudy Pool Water

Pools can be finicky at times, but there’s usually always a reason why it looks less than perfect. If your pool looks cloudy, there’s a solution to help you bring it back to its swimmable state.

This guide will help you understand what makes a pool cloudy, the different types of cloudy pools, and how to fix them.

Why Is My Pool Water Cloudy?

When contaminants enter your pool, your sanitizer starts attacking them. But when there are too many contaminants to fight or the contaminants are too large, you’ll end up losing sanitizer quickly. And without enough sanitizer, pathogens and bacteria will grow in the water.

The cloudiness comes from small particles in the water that reflect light. These particles can be introduced into the water by the environment, humans, and chemicals, or can be the leftover particles of evaporated chemicals.

Cloudy pool water is not only harmful to your pool filter, but it is also dangerous to swim in because it can be full of harmful bacteria, such E. coli and Legionella, and it is a drowning hazard.

Here are the most common causes of contaminants entering pools and making the water cloudy.

Human Causes

Unless you shower right before jumping in your pool, you’ll likely introduce contaminants into the water. These contaminants include sunscreen, beauty products, sweat, and urine. And it’s these human contaminants that require you to keep adding sanitizer to the water.

Environmental Causes

Sunlight causes sanitizer levels to deplete quickly in pool water. When you add chlorine to your pool water, the ultraviolet (UV) rays of sunlight break down the hypochlorite ions of the chlorine, causing them to evaporate into the air instead of sanitizing your pool water.

Insects, bird droppings, stormwater run-off, leaves, dust, pollen, mold, sand, and other natural debris also make sanitizer work harder, hogging sanitizer and causing cloudy water.

Algae also use up sanitizer quickly, so you will need large amounts of chlorine and bromine to kill off algae blooms. Along with cloudy pool water, algae blooms will also cause green pool water.

Chemical Causes

Excessive amounts of pool chemicals can cause cloudy pool water. These include:

  • High pH—makes water less acidic with a tendency to form scale in the pool and plumbing, which causes filtration problems, makes sanitizer less effective, and results in cloudy water;
  • High alkalinity—will also form scale and not stabilize pH properly;
  • High calcium hardness—creates a flaky buildup in your pool, clogging the filters and clouding the water;
  • High calcium hypochlorite—overuse of granular calcium hypochlorite shock treatment can also cause cloudy pool water.

Another cause of cloudy water is a poor filtration system. A clogged filter, dying pump, or not running your filtration system for a minimum of eight hours each day can all contribute to cloudy water.

Two Important Details About the Cloud-Causing Particles

To help you better understand how the treatment works for cloudy pool water, let’s look at the two most important characteristics of the particles responsible for creating cloudy water.

1. They’re Small

The particles introduced into pool water range in size from 0.5 to 5.0 microns (a grain of sand is about 1,000 microns). So these particles are too small to be caught by the filter and filtered out properly.

2. They Carry a Negative Charge

These particles also have a negative electric charge that causes them to repel each other and hang in isolated suspension in the water.

So to effectively treat these tiny particles that repel each other, treatment often involves changing the particles’ electric charge so they will stick together and become large enough to be caught by the filtration system and properly filtered out of the water.

Clarifiers and flocculants are pool water treatment chemicals that neutralize the particles’ electric charge, so they bond together, get filtered out, or sink to the bottom of the pool to be vacuumed away.

Determining the Cloudiness Level and How to Fix It

There are different levels of cloudiness for pool water. The solution you use to clear your pool of its cloudiness will depend on the level, or severity, of the cloudiness.

Dull or Flat + Fix

Dull or flat pool water will still be blue but will no longer have its regular sparkle and shine.

The fix:
  • Start the pump;
  • Adjust the pH to between 7.2 and 7.6;
  • Add clarifier to your pool in the amount recommended for your pool size;
  • Run the pump and filter system for 12 hours.

Hazy + Fix

Hazy water is no longer clear, but you can still see the bottom of the pool although not distinctly.

The fix:
  • Start the pump;
  • Adjust the pH to between 7.2 and 7.6;
  • Add clarifier to your pool in the amount recommended for your pool size;
  • Run the pump and filter system for 12 hours.

Cloudy + Fix

Cloudy water looks milky. You can still see the bottom of the pool in the shallow end but not in the deep end.

The fix:
  • Start the pump;
  • Adjust the pH to between 7.2 and 7.6;
  • Add the recommended amount of clarifier for your pool size;
  • Run the pump and filter system for 8 hours;
  • Turn off the pump for 8 to 10 hours;
  • Thoroughly vacuum the pool and run to waste;
  • Run the pump for 4 hours.

Opaque + Fix

Opaque water is so milky that you can no longer see the bottom of the pool at all.

The fix:
  • Add water to the pool so the level is above the skimmer box line;
  • Adjust the pH to 7.8;
  • For a pool cartridge filter, remove the cartridge, and for a sand filter, set it to recirculate;
  • Start the pump;
  • Add the recommended amount of flocculants for your pool size;
  • Run the pump for 2 to 3 hours;
  • Turn off the pump for 10 to 12 hours;
  • Thoroughly vacuum the pool and run to waste;
  • If the pool is still cloudy after completing the above steps, keep the pump off for 24 hours, then vacuum again and run to waste.

How Do I Test the Pool Water? How Often Should I Test It?

You can test your pool water manually with a testing kit, or you can bring a sample of your pool water into your local pool services for a computerized water analysis.

Follow these pool water testing tips to keep your water clear, safe, and balanced:

  • Free chlorine—check the chlorine levels two to three times per week. Testing free chlorine shows how much chlorine is available for sanitation.
  • pH—check the pH level when you check the chlorine. A balanced pH will help make the chlorine an effective sanitizer.
  • Total Alkalinity—test the total alkalinity once a week. Total alkalinity affects the stability of your pH levels.
  • Calcium Hardness—test the calcium hardness once a month.
  • Total Dissolved Solids (TDS)—test the TDS at least once a month. If it’s too high, it will hinder the efficiency of the other chemicals.
  • Metals—test the metal levels every three months to determine if there are any metals in the water that need to be removed.
  • Salt—for salt chlorination systems in saltwater pools, test the salt levels once a month.

Also, be sure to test your pool water after extreme weather. Periods of extreme heat will evaporate pool water, and the chemicals will lose their effectiveness. And plenty of rain will decrease the pH levels, which makes water uncomfortable to swim in and can damage pool surfaces and equipment.

Getting the Pros to Test Your Water and Balance Your Pool for You

Better yet, get the pros from a local pool service to test and balance your pool water for you. They can add all the necessary pool water treatment chemicals to keep your pool safe, clear, and sparkling clean all summer long.