A swimming pool is a great way to stay cool during the hot Dallas summers, but dealing with algae growth can be a frustrating challenge. The sight of green, cloudy water is not only unappealing but also a sign of an unhealthy pool. Many pool owners frequently ask, “Why is my pool water green?” The most common cause is algae, microscopic plant-like organisms that grow in contaminated, stagnant, or chemically imbalanced water.
If your pool water is turning green, don't worry. This guide will walk you through how to fix a green pool and prevent algae from taking over your swimming oasis. Whether you have a traditional chlorine pool or need tips on how to fix a green saltwater pool, following these steps will help you restore your pool.
Why Is My Swimming Pool Green?
The most obvious culprit is algae. It can grow rapidly under the right conditions and turn your pool water green, making surfaces slippery. Whether you have a chlorinated pool or a saltwater pool, algae can enter your pool and infest it in no time.
So, the first step in treating the problem is recognizing the signs early and acting urgently. It's time to take action if you notice any of the following:
- The water looks cloudy and has a green tint, ranging from light to dark green.
- The pool walls and floor feel slimy.
- Water clarity decreases, making it hard to see the bottom.
- Your pool filter is working harder but not improving water quality.
Types of Algae That Affect Pools
Although green water is usually caused by green algae, other types of algae can affect your pool too. They also make the water look murky and alter its color.
Green Algae
This is the most common type of algae, and it's usually what most people think of when they hear about algae. Its color resembles that of green vegetation, appearing under the water and on the surface or sometimes as moss-like clumps floating in the pool. It spreads rapidly and can also be found on pool walls and steps. In some extreme cases, it may appear as a large amount of debris where you can’t see the bottom.
Mustard Algae
It’s also called yellow algae and looks like sand or dirt. It usually thrives in the shady parts of the pool such as the corners and the bottom. Sometimes it begins in the spa and spreads to the pool. To tell it apart from a pile of sand, you can use an antimicrobial pool brush. Just give it a nudge and see whether it disperses instantly–if it does, you’re dealing with mustard algae.
Mustard algae can grow outside the pool on things like pool equipment, toys, swimsuits, etc. Therefore, to eliminate mustard algae, you need to sanitize almost everything that comes in contact with the pool water.
Black Algae
Black algae is the toughest type of algae to eradicate, as it digs its roots inside the surfaces it grows on. Instead of the typical green color of vegetation, it appears as black spots on pool surfaces. It usually grows on rough and textured surfaces that offer a secure grip for it to cling to. It may indicate that the plaster is old and needs to be replaced.
It has a waxy outer layer that makes it resistant to regular chlorine. Eradicating black algae requires stiff brushing, chlorine tablets directly on spots, and silver-based algaecide.
Common Causes of Algae Growth
Algae growth can happen quickly if the conditions are right. Here are the most common reasons your pool keeps turning green:
- Poor water circulation: Low flow or dead spots in the pool allow algae to settle and multiply.
- Insufficient water circulation: If the pool pump isn’t running properly, then you are likely to see algae growth.
- Unbalanced water chemistry: Incorrect pH, alkalinity, or chlorine levels provide the perfect environment for algae.
- Low chlorine levels: Without enough sanitizer, algae can bloom rapidly.
- Dirty or clogged filter: A poorly maintained filter cannot properly remove contaminants.
- Organic contamination: Algae spores can enter the pool through leaves, dirt, or other organic debris that falls into the water. Also, swimmers can introduce bacteria from lakes or beaches, especially if they wear the same swimsuit in the pool without properly washing it first.
- Warm temperatures and sunlight: Algae thrive in sunny, warm water, especially when chlorine levels drop.
How to Fix a Green Pool
Before you start the cleaning process, it's important to assess your pool's equipment and water balance.
Pre-Treatment Inspection and Adjustments
Here are some key things that you need to ensure before starting the treatment:
Check the filtration system: A faulty or dirty filter can make the cleaning process ineffective. Repair or replace it if necessary.
Ensure that the Pool Pump is running adequately: An underutilized pool pump may result in algae.
Detect leaks: Water loss can affect chemical balance, making it harder to maintain a clean pool.
Assess plumbing issues: Poor circulation can contribute to algae growth, so inspect and repair pipes if needed.
Optimize pool automation: If you have an automated system, adjust it to run the pump longer during treatment.
Treating Green Pool: Step-by-Step Guide
If you’re dealing with green algae, it’s crucial to act fast before the issue worsens. Follow these step-by-step guidelines from the experts at ASP (America’s Swimming Pool Company):
1. Remove Debris, Brush, and Vacuum
Use a pool net to scoop out leaves, twigs, and other debris that may be harboring algae. Then, grab your pool brush and scrub every inch of the pool. Be sure to reach the walls, stairs, and any tight corners where algae may be hiding. This will help loosen algae, making it easier to remove.
The type of brush you need depends on your pool’s surface. Use a nylon bristle brush for fiberglass pools and a steel bristle brush for concrete pools.
Once you’ve thoroughly brushed the pool, vacuum it carefully, making multiple passes if necessary.
2. Test Alkalinity & pH
Next, check your pool’s alkalinity and pH levels. Alkalinity measures how well the water resists pH changes, while pH determines the water’s acidity. When properly balanced, these factors help maintain clean and safe swimming conditions.
Adjust your levels as needed. Aim for a pH of 7.2-7.8 and an alkalinity between 80-120 PPM.
3. Shock the Pool Two or Three Times
Shocking your pool should be part of regular maintenance. This process involves adding chemicals to balance the water and increase free chlorine levels.
For green algae, apply a double or triple dose of shock to eliminate algae and bacteria. Always follow package instructions carefully and wear protective gear, such as gloves and goggles, when handling chemicals.
4. Turn the Pool Filter On
After shocking the pool, run the filter to remove dead algae and other debris. This step helps clear up the water and restore its cleanliness. You might need to backwash or replace filter cartridges to prevent dead algae from re-entering the water.
5. Repeat Until Clear
If the water is still green or cloudy after completing these steps, repeat the entire process. Continue until the pool water is completely clear and free of algae.
How to Prevent the Pool From Turning Green Again
Regular maintenance is the key to preventing algae growth. Follow these tips to keep your pool clear and healthy:
- Maintain proper chemical balance: Test water regularly and adjust pH, chlorine, and alkalinity levels as needed.
- Brush and vacuum weekly: This removes debris and prevents algae buildup.
- Ensure proper circulation: Run your pool pump for at least 8-12 hours per day to keep water moving. It is recommended that the pool pump run daily for as many hours as the top temperature determines. Example: 1 hour for each 10 degrees = 8 hours for temps in the 80’s or 10 hours for temps in the 100s. Variable Speed pumps may need to be reprogrammed for maximum pump efficiency during the Summer in Dallas.
- Limit sunlight exposure: Use pool covers, shade, or umbrellas to reduce sunlight, which fuels algae growth.
- Inspect for cracks: Algae can hide in cracks or crevices, so repair any structural damage.
- Wash your swimsuits: Avoid wearing the same swimsuit in the pool that you wear for bathing elsewhere. This prevents external bacteria and organisms from entering the pool.
Why Does My Pool Keep Turning Green After Treatment?
If your pool keeps turning green despite treatment, the cause could be inadequate cleaning or an issue unrelated to algae.
High Copper Level
The green hue might not have anything to do with algae, to begin with. Chlorine interacting with high concentrations of copper can turn the pool water green. Check your pool’s copper level, and use calcium chloride to adjust it.
Alkalinity & pH Imbalance
If your pool is still green after the treatment, recheck your pool’s chemical balance. Bringing it to the correct levels might be exactly what your water needs to prevent algae and other unwanted contaminants.
Poor Cleaning
If your pool is not cleaned properly in the first place, it might get infested by algae again and turn green. Be extra careful when cleaning your pool to ensure the elimination of green algae for good.
Pool Filter Malfunction
Always ensure that the pool filter is properly functioning, as a lack of proper filtration and circulation leads to algae bloom. Clean your filter carefully and repair or replace it if needed.
Final Thoughts
Green pool is a common problem in Dallas, but it can be controlled and prevented with the right approach. By maintaining proper chemical balance, cleaning your pool regularly, and ensuring good circulation, you can keep your pool sparkling clean.
If your pool keeps turning green in Dallas, consider professional assistance. ASP’s Green-to-Clean pool recovery service can transform your unsafe, algae-infested pool into a crystal-clear oasis in just 3-5 days. Our certified professionals will remove debris, kill algae, and balance your pool’s chemistry to ensure a healthy swimming experience. Call us today at (214) 740-3814
FAQ's
How do I get rid of green water in my pool?
Getting rid of the green hue in your pool involves identifying the root cause of the problem. The most common reason behind the green color is algae, which requires proper brushing, vacuuming, and shock treatment to be eradicated.
How do you get rid of green water fast?
When trying to get rid of green water, you need to eradicate algae. It's best to stick to brushing, vacuuming, filtering, and shocking the pool to completely rid your pool of algae and restore its clarity.
Can too much chlorine make a pool green?
Yes. Although chlorine is needed to prevent algae growth, a high chlorine level can also oxidize the metals, turning your pool green.
What is the main cause of a green pool?
There can be several reasons behind a green pool such as the oxidization of metals, debris, or other contaminants. However, the most common cause of a green pool is green algae.
Is it safe to swim in a green pool?
No, it’s not safe to swim in a green pool. The green hue and murky appearance of the water is a sign of algae infestation, bacterial contamination, and a lack of proper filtration. Therefore, swimming in a green pool is not recommended.
What is the fastest way to remove chlorine from water?
One of the safest and most effective ways to reduce chlorine is using sodium thiosulfate, but be careful about the quantity when doing it.