How To Clear Up Murky Pool Water

Solved! What to Do About Cloudy Pool Water

Clear up cloudy pool water with these straightforward fixes, so you can get back to enjoying your swimming pool.

closeup of a young caucasian man cleaning the bottom of a portable swimming pool placed in the backyard with a brush mounted in a telescopic pole

Photo: istockphoto.com

Q: Every year we struggle to keep the pool water clear, but even when we run the filter 24/7 it becomes cloudy within a few days. Other than this, the pool functions without an issue. What should I do? Is this a problem we are stuck with, or is there a solution to clear up the water?

A: Cloudy pool water is a common occurrence that most pool owners struggle with at least once every swimming season. The good news is that most of the fixes are relatively simple, but it may take some trial and error to determine the cause of the cloudy pool water.

Cloudy water may still be safe to swim in, but if the chemicals are not balanced, then swimmers can experience red eyes, irritated skin, and rashes. If the cause is environmental factors, it can usually be cleared up with a clarifier and regular cleaning. If the water chemistry is balanced and environmental factors have been ruled out, then the problem is likely with the filtration system. If this is the case, then you may have to invest in replacement parts for any worn-out or broken pieces of the system.

Related: The Best Robotic Pool Cleaners

A hand holding a water test kit with pool water background.

Photo: istockphoto.com

Identify the cause of cloudy pool water.

There are three main causes for cloudy pool water, including poor filtration, chemical imbalances, or environmental factors, like nearby construction, trees, or wildlife.

Filter and pump problems can be caused by a range of different issues. If the system is only run for a few hours every day, it may not be able to clean the entire pool. If it runs regularly, then the issue may be a worn or broken part. Other mechanical issues that can arise include clogged filter media, poor water flow directionality, and a full skimmer basket.
Chemical imbalances are a common cause of cloudy pool water. Testing the cloudy water with a pool water test kit will likely reveal that the pool water has improper levels of chlorine, imbalanced pH and alkalinity, or very high calcium hardness levels. However, sometimes a balanced pool will become cloudy immediately after being shocked. This typically clears quickly on its own and shouldn't be considered a problem.
Environmental factors include pretty much everything around the pool like severe weather, wildlife, construction, trees, pool algae, and people. These factors can cause dust, pollen, and algae blooms to cloud the pool. While people may be the most common environmental cause with various hair products, skin products, and makeup that seeps into the water, people also bring dirt, sweat, skin, hair, and oils into pool water.

How to fix cloudy pool water caused by the environment.

If the chemical composition of the water is balanced and the filtration system seems to be functioning normally, then the cloudy pool water may be caused by an environmental factor.

Construction, severe storms, and large groups of people can dump high levels of dirt, dust, and other debris into the pool water. Trees, wildlife, and algae spores cloud the water with pollen, sweat, algae blooms, hair, feathers, and other organic matter, making it difficult for the filter to quickly clean the water.

Don't want to do the dirty work yourself?

Get free, no-commitment project estimates from pool contractors and more near you.

However, fixing these environmental issues is typically as easy as adding a pool clarifier to the water. This chemical acts as a coagulant, bonding together the loose dirt, pollen, and other small debris, which increases the size of the loose particles and makes it easier for the filtration system to pick up the particles.

After applying the pool clarifying coagulant, it can take up to 24 hours for the pool water to clear up. Unfortunately, environmental factors, like nearby construction or wildlife, may be outside of your ability to control. If the pool is frequently contaminated, add a pool clarifier to your regular pool maintenance schedule to help maintain the clarity of the water.

Swimming pool cleaning system

Photo: istockphoto.com

How to fix cloudy pool water caused by poor filtration.

When a pool clarifier doesn't work and the water chemistry is balanced, then the cause of cloudy pool water is likely mechanical. The range of pump and filtration problems starts with simple human error and extends to worn-out or broken parts.

During the swimming season, the pump and filtration system need to run for at least 8 hours every day to properly clean and filter the pool water. If it's only on for a few hours daily, then the system won't have time to clean the pool, leaving the water cloudy. The jets also need to point downward in order to move the water at the bottom of the pool through the system.

Regularly empty the skimmer basket and backwash the pump and filtration system to help prevent clogs. If a clog occurs in the skimmer line, it can reduce the flow of water through the filtration system and can burn out the pump, so it's important to turn off the system immediately. Clear the clog or hire a pool repair professional to clear the clog before restarting the filtration system to avoid further repairs.

If human error, regular maintenance, and clogs aren't the problem, check the pump and filtration system for any broken parts that could impact the water pressure or the ability of the system to clean debris. If any parts are severely worn or broken, they will need to be replaced. The filter media also can become dirty and clogged over time. It needs to be removed and chemically cleaned with a filter cleaner. However, some people may prefer to replace the filter media.

RELATED: 11 Ways to Make a Small Pool Work in Your Backyard

Equipment for testing the quality of pool water and cleaning a pool

Photo: istockphoto.com

How to fix cloudy pool water caused by a chemical imbalance.

If the problem is a chemical imbalance, then it's easy to determine how to fix the issue. First, use a pool test kit to test the chemical composition of the pool water. Invest in an accurate pool test kit that tests for chlorine levels, bromine levels, pH levels, total alkalinity, calcium hardness, and cyanuric acid.

Low levels of chlorine or bromine may not be able to kill algae spores, resulting in algae blooms and cloudy pool water. Chlorine levels should range between 1 to 3 parts per million (ppm) and bromine has a slightly wider range between 2 to 6 ppm. Shock the pool with a high level of chlorine or bromine to rapidly return the pool water to a balanced level.

Imbalanced alkalinity and pH also could result in cloudy water, and it can be a safety hazard. The total alkalinity of the pool should remain between 8 to 120 ppm and the pH needs to be monitored.

A pH between 7.2 to 7.8 is best.
A pH between 7 to 7.8 is safe.
A pH of 7 or lower is considered acidic and can cause itching, burning, and rashes.
A pH balance above 7.8 is a basic solution that can burn and irritate the eyes.

Raise the pH and alkalinity by adding alkaline products like sodium bicarbonate (baking soda) or lower the pH and alkalinity with chemical additives made with muriatic acid or sodium bisulfate.

The calcium hardness should fall between 180 to 220 ppm and it can be lowered by adding pool flocculant to clump the calcium. These clumps will clog the filter. To remove them, vacuum the waste instead of pulling the debris through the filter. Raise calcium hardness by adding calcium chloride to the pool water.

Cyanuric acid is a stabilizer that prevents chlorine from breaking down under direct sunlight. Keep levels between 30 to 50 ppm to reduce the production of harmful chloramines. Levels of cyanuric acid can be lowered by draining a portion of the pool and refilling it with clean water. The levels can be raised by adding a stabilizer with cyanuric acid or chlorine tablets that come with a stabilizer in the formula.

Residential inground swimming pool in backyard with waterfall and hot tub

Photo: istockphoto.com

Ways to prevent cloudy pool water in the future.

After the problem is solved and the pool water is clear, it's important to take steps to prevent cloudy pool water from recurring. Check the jets in the pool to make sure that they are angled downward so that the water on the bottom of the pool circulates through the filtration system. It's also advised to run the pump and filter for at least 8 hours every day during swimming seasons and backwash the pool once per week.

Use a clarifier to help deal with ongoing environmental factors, and test the pool water two to three times per week to ensure that the chemical composition is balanced. If the tests begin to trend towards a chemical imbalance, add the appropriate chemicals to the pool to bring the pool water back to a balanced state. This means that the pH should be within 7.2 to 7.8 and the chlorine concentration should fall within 1 to 3 ppm.

Related: Planning Guide for Above-Ground Swimming Pools

Find trusted local pros for any home project