Swimming in clean, crystal clear water is one of the greatest joys in life. Who doesn’t love to swim on a nice hot day with friends, family, or loved ones?
However, there are times when your swimming pool water doesn’t look as appealing as it should. Debris, dirt, leaves, and other contaminants can make the entire pool appear murky. Brown pool water occurs due to a chemical reaction, copper stains, or impurities that can significantly affect your swimming experience.
This article will explain how brown pool water is caused and provide tips on preventing and removing this problem.
What Causes Brown Pool Water
Brown pool water can be distressing for pool owners. It’s therefore essential to understand the reason why your pool water turns brown. Several causes of brown pool water include:
Chlorine can react with the metal in the pool water. When this occurs, it can strip away particles from the metal suspended into the water surface, thus creating a brownish tint. Chlorine also reacts with oils and organic materials in the swimming pool, which can form a brown film on the surface area of the water.
Many pool owners believe that adding chlorine directly to their pool is enough to keep it clean and sanitary without worrying about other additives. However, even with an adequate dose of chlorine in your swimming pool, deposits can still accumulate on the walls and floor of your swimming pool, which can stain the pool surfaces and cause brown water.
Metal stains can also cause brown pool water. Iron is one of the more common metal stains in swimming pools. Iron ions react with the chlorine in the pool water. This leads to the formation of brown sediments, which can stick to the sides and bottom of your swimming pool, causing it to appear murky or brownish.
Oxidized iron causes the pool water to have a metallic odor and bitter taste. If there are high iron levels in the water, it can turn a brownish-red tint. Stains below the pool surface may appear as light yellow patches on your floor or walls.
Chemical reactions occur when pool chemicals are introduced to the water, leading to stains when they react with other compounds in the pool water. When these particles rise to the surface of the water, they cause light-colored dirt and debris on the surface area of your swimming pool.
Additionally, brown water may result when you shock your pool with chlorine inappropriately. Some free chlorine may be oxidized if the chlorine is added directly to chlorinated water. This causes a brown film on your pool floor or sidewalls.
It’s best to maintain your swimming pool regularly, ensuring that chlorine is being released into the water at regular intervals to combat brown water. This will prevent any residual build-up on the walls or floor of your swimming pool, which can result in dirt and debris ending up in the water column.
Metal staining is the typical culprit of brownish pool water. Different metal compounds like iron, magnesium, calcium, copper, or manganese react with the water molecules and chlorine resulting in brown water.
Different metals are more likely to stain your pool than others. Iron stains are most common, which is why many pool owners notice brown streaks on the walls and bottom of their pools after they have been swimming in them for some time.
To prevent metal staining, you should regularly check the chlorine levels in your pool. This will help to keep your water clean and your pool pristine. You can also sample the pool water every two weeks and adjust the chlorine level as necessary.
If you notice any brown water in your swimming pool, use a metal sequestering agent to remove it. This will break down and bind with these metal stains to prevent further staining or discoloration of your pool surfaces.
- Sequa-Sol sequestering agent provides fast and effective protection against pool staining and scaling
- Powerful formula holds minerals in solution even in chlorine, bromine and strong UV sunlight
- Provides fast and effective protection against pool staining and scaling
- Protects pool equipment; use as a part of weekly maintenance program
Algae is another common cause of brown pool water. Excess phosphates and nitrogenous organic compounds (NOCs) can feed algae blooms. Algae thrive in swimming pools rich in nutrients and with unbalanced pH levels. Bad water chemistry and warm water temperatures can also trigger algae blooms and cause brown pool water.
Apply algaecides regularly to your pool to prevent the growth of algae and exacerbate any existing algae blooms. Use a pool brush to scrub the sides of your swimming pool to remove any algae build-up.
- BENEFITS: Kills and prevents all algae types including green, black and mustard algae in your swimming pool so you can enjoy your summertime fun
- USE: Apply directly to the pool for easy DIY pool care
- COMPATIBILITY: Great for vinyl-lined and saltwater pool systems
Regularly clean and balance the pool chemistry to combat algae growth and prevent metal stains from occurring often. Consider also replacing your filter media to prevent the build-up of algae. The dead algae particles will sink to the bottom of your swimming pool floor, where you can either filter them out by the skimmer or vacuum.
How to Get Brown Pool Water Clear
Brown pool water feels unhygienic and appears disgusting. Leaving spas, hot tubs, and above-ground pools with brown water for long can cause permanent stains. Brown stain removal can be a real chore whether you have a swimming pool or a hot tub. To keep your pool water clear and to maintain its sparkling look, take the following steps:
Ascorbic Acid (Vitamin C)
Ascorbic acid is a mild oxidizing agent that breaks down proteins and clears up brown water. You can use it as a vitamin supplement to prevent your pool from becoming smelly or eliminate stains caused by metals.
To do this:
- Mix one pound of ascorbic acid powder with one liter of water for every 10,000 gallons of water.
- Stir thoroughly until the powder has dissolved.
- Apply the mixture on your pool’s surface, turn on the pump and wait for around 30 minutes to one hour for the solution to circulate evenly in your pool.
Turn Off Pool Pump
After an hour of running your pool pump, the brown stains will start being lifted and float on the water surface. Allow at least one hour for all the brown pool water stains to get lifted. Then, you can turn off the pump.
Remove Iron From Surface
- Protecting new pool surfaces from stains
- Preventing scale on salt system equipment
Gently skim the iron stains from the water’s surface with a skimmer basket making sure not to damage your pool filter. Next, you can add 32oz of Revive to remove all the iron particles in the brown stain. Revive turns all the stains into sediments that sink to the pool’s surface. Leave your pool overnight, and don’t use it for at least 24 hours.
Clean Remaining Debris
After 24 hours, it’s time to clean any remaining debris, including at the bottom of the swimming pool. Use your pool vacuum to clean up all the junk that has settled to the bottom. You may also remove the scum line found at the waterline by brushing and vacuuming it off.
Brown Pool Water Prevention
Clearing brown water from your pool can be tedious and time-consuming, so preventing it from happening should be your top priority. Below are several tips you can use to avoid brown water from in your swimming pool:
- BENEFITS: Increases the chlorine level in swimming pools to kill bacteria and algae to keep your pool water clear and ready for fun all season long
- USE: Apply directly to pool water as needed; Test pool water and shock weekly to keep free available chlorine levels between 1 and 4ppm
- COMPATIBILITY: Effective for all swimming pool types including pools with liners and Gunite pools, and saltwater pool systems
To keep your pool water crystal clear and improve the water quality, consider pool shocking your pool once every week. Shocking means adding chlorine or non-chlorine pool chemicals in the pool water to raise the “free chlorine” level.
High “free chlorine” levels destroy contaminants like bacteria, algae, and chloramines and stop their growth by preventing the formation of organic compounds. If you’re adding chlorine, it’s best to add chlorinating liquid or granules. You should always read and follow manufacturer instructions regarding pool shock.
Install an automatic chlorinator to monitor the levels of chlorine in your swimming pool so that you can keep track of whether they are dropping below-recommended levels. Shock your pool in the evening after you finish all swimming. This will also prevent chlorine exposure to the sun’s rays, reducing its effectiveness.
Regular pool maintenance is the best way to prevent your swimming pool’s water from turning brown. Routinely remove any debris in the pool before it can cause any problems. Leaving your pool with scum lines, sticks or leaves can encourage algae growth in the pool. Resulting chemical reactions can cause the water to turn brown.
Use a vacuum cleaner or leaf net to remove any debris in your pool that can cause stains, then use the brush to scrub off any scum lines you might have. This should be done regularly to remove dirt before it turns into stains.
You can clean your pump filter baskets and traps for dirt or debris every time you clean your pool to avoid the dirt from being pushed back into your pool. It is also advisable to vacuum the pool floor every week and brush the tile lines regularly.
Regularly Test Pool Water
- Features a photometer which gives you a digital reading of test results.
- Water resistant housing and carrying case provided.
- Tests Free Chlorine, Total Chlorine, Bromine, PH, Alkalinity, Calcium Hardness, and Cyanuric Acid.
- Uses liquid reagents for all test factors except Cyanuric Acid, which uses tablets.
It is important to test your pool water regularly to check its pH, chlorine, alkalinity, and hardness. This helps know your pool chemistry to avoid under or over-treating it with chemicals.
Ensure you’re using the right amounts of chemical cleanser specific to your pool type to avoid bacteria build-up, cloudy water, and surface damage. Keeping the water chemicals balanced ensures your pool equipment stays in great shape for a long time.
Test your pool water two to three times a week to determine the PH levels, total alkalinity, free chlorine level, and total dissolved solids. This will show you what’s happening in your pool water, making it easier to know how much chemicals are needed to balance your pool water.
Free chlorine is the amount of chlorine available to kill contaminants in your pool. High levels of free chlorine are crucial to keep your swimming pool water clean and prevent bacteria from attaching to the pool walls.
Free chlorine levels should always remain at 1-3 parts per million (ppm) to control algae growth. If you have brown water in your pool, there is a high level of organic chemicals that react with chlorine, producing a rusty color.
When adding chlorine to your pool, follow package instructions closely to avoid over-treating your pool which can cause the free chlorine levels to drop too low, resulting in a “chlorine demand” and brown water. Instead, use a chlorine shock treatment weekly to raise your free chlorine levels if they drop too low.
Total chlorine is the amount of both free and combined chlorine in your pool. The combined chlorine is the amount of chlorine that’s already reacted with a substance, such as a human body.
The total chlorine level should stay at 1.0 ppm to 3.0 ppm for effective sanitation and safety in your pool water. However, it can be challenging to tell if you have low or high total chlorine levels, so it’s best to measure free chlorine levels instead.
If your pool water is turning brown, you will need to add more free chlorine into your swimming pool rather than using chlorinate tablets or liquid shock, which can cause damage to your filters and heaters.
Your pool water’s pH level is the most critical factor in determining if you have brown pool water or clean, turquoise blue color. The optimum pH level in your swimming pool is between 7.2-7.6 to ensure that it’s safe for swimmers and prevents damage to the equipment.
If your pool has high levels of metals or low pH levels, this will cause brown stains to form on pool walls and steps. You should test your pool water’s pH level at least two to three times a week because high levels of chemical use can affect the amount of acid needed for your swimming pool.
If you notice that the water in your pool is turning yellow, then it’s likely that you have low chlorine levels. High levels of organic substances in your pool water can also cause brown stains to form, making it harder for chlorine to clean the pool.
Your pool water’s alkalinity level refers to the amount of acid needed to lower the pH levels of your swimming pool. High total alkalinity causes low pH levels, which reduces chlorine effectiveness and causes brown stains to form around high metal areas of your pool.
High total alkalinity can be caused by organic materials in your pool, balancing your swimming pool water, using reducing agents, and having a pH level that’s too low. The recommended total alkalinity level for pool water is 80-120 ppm.
The best way to fix high alkalinity is to use a non-chlorine shock treatment to lower the pH levels in your swimming pool, so it’s effective again. It’s also important to check the amount of organic materials in your swimming pool and regularly clean the pool.
- Increases Cyanuric Acid Level
- Decreases Chlorine Loss due to Sunlight
- Reduce Chlorine Consumption up to 25%
- Contains 100% Cyanuric Acid
- Improves the effectiveness of chlorine
Cyanuric acid is an excellent addition to your regular pool maintenance. It protects chlorine against the sun’s UV lights, weakening its effectiveness. Unfortunately, this significantly affects the water chemistry, which can cause algae to bloom that makes the water turn brown.
Cyanuric acid can be added to your pool in various forms, including liquid or dry chlorine. It’s best to add cyanuric acid once a week when the daily UV levels are at their highest.
Adding too much of this chemical can cause damage to pool equipment and may even affect the pH, total alkalinity, and calcium hardness levels of the water. Ensure you follow the manufacturer’s recommended dosage rates.
Brown Pool FAQ
Now that you know what causes brown water in your pool and how you can prevent it from occurring again, it’s vital to look at some of the frequently asked questions about brown pool water.
How Do I Get Rid of Brown Algae in My Pool?
If you have brown algae bloom in your pool, the water chemistry is likely out of balance. First, shock your pool with chlorine, then add a copper-free algaecide. Leave the pool overnight, then vacuum and backwash the filter after 24 hours. Repeat this process until the pool is clean and the water is crystal clear.
Is It Safe to Swim in Brown Pool Water?
No. It’s unsafe to swim in a pool with brown water since it’s unhygienic. In addition, the water contains harmful bacteria and other materials which can cause infection and illness. Algae is also slippery, which can cause injuries when you step on them.
How Do You Fix Oxidized Pool Water?
Oxidation occurs when iron reacts with the water chemicals. It can affect pool equipment and cause stains to appear on the walls and steps of your swimming pool. To fix oxidized pool water, you need to shock treat the water using pHin and keep the water pH level between 7.2 and 7.6 using an acid blend or non-chlorine shock treatment. Then, brush and vacuum the pool until the brown stains are completely gone.
The Bottom Line
Swimming in a pool with brown water can be very harmful and dangerous. It contains bacteria and other materials that can cause you to contract an illness or injury when swimming. With this guide, you know what causes the brown color in pool water, how you can prevent it from occurring, and what action to take if it does occur.
For over 15 years, Sean Moore has been sharing his love and enthusiasm for swimming pools and hot tubs with everyone he knows. His goal is to help everyday people DIY their maintenance to save money by teaching how to properly take care of your equipment, safely and correctly balance chemicals, and extend the life of your water oasis.
Pricing on this page was last updated on 2022-11-26