April 9, 2026

Common Types of Pool Algae and How to Get Rid of Them

Common Types of Pool Algae and How to Get Rid of Them

Nothing ruins a sunny afternoon faster than walking outside and finding your once-sparkling pool turned into a green, cloudy, or slimy mess. If you live in Dallas-Fort Worth, you already know how quickly Texas heat and humidity can turn a healthy pool into an algae playground. Understanding the different types of pool algae is the first step toward fixing the problem and making sure it doesn't return next week.

At Anomaly Pool Services, we have helped hundreds of homeowners across DFW eliminate algae blooms and restore crystal-clear water. In this guide, we break down the most common different types of algae in pools, how to identify each one, and the most effective ways to get rid of them for good.

What You'll Learn in This Guide

  • What pool algae is and why it grows so fast in DFW
  • The 4 main different types of pool algae and how to identify each
  • Step-by-step methods to remove algae from pool surfaces
  • Why algae keeps coming back and how to prevent it
  • When it's time to call a professional pool cleaning service

What Is Pool Algae and Why Does It Form?

Pool algae is a tiny, plant-like organism that thrives in warm, sunlit water with poor sanitization. Algae spores travel through the air, on swimsuits, on pool toys, and even in rainwater. Once they land in your pool and conditions are right, they multiply fast, sometimes overnight.

Common Causes of Algae Growth

  • Low chlorine levels or imbalanced pH
  • Poor water circulation or a clogged filter
  • Hot Texas summers and intense sunlight
  • Heavy rainstorms washing contaminants into the pool
  • Phosphates and organic debris like leaves, pollen, and sweat
  • Skipped weekly maintenance or shock treatments

Why Is My Pool Green After Rain?

If you have noticed your pool turning green after a Texas thunderstorm, you are not alone. Heavy rain dilutes chlorine, washes in phosphates and organic debris, and shifts pH levels. These changes create the perfect environment for green algae to bloom within 24 hours. Running your pump longer and shocking the pool after storms is the easiest way to stop this from happening.

The 4 Main Types of Swimming Pool Algae

Not all algae is the same. Each type behaves differently, requires a unique treatment approach, and tells you something specific about your pool's chemistry. Here are the four most common types of swimming pool algae you will face in DFW backyards.

Green Algae - The Most Common Type

Green algae is the algae most homeowners recognize instantly. It is also the easiest to treat, but the fastest to grow.

How to Identify Green Algae

  • Cloudy, swampy-looking water
  • Green tint that ranges from light to dark
  • Slippery walls and floor
  • Visible film on the waterline

How to Get Rid of Green Algae

If you are wondering what to do when pool water is green, follow these steps:

  • Test and balance the water (pH between 7.2 and 7.4)
  • Brush all walls, floors, steps, and corners
  • Triple-shock the pool with chlorine
  • Run the pump 24 hours a day until water clears
  • Add a quality algaecide to prevent regrowth
  • Vacuum debris and clean or backwash your filter

If your pool has gone fully green and you cannot see the bottom, our green to blue pool service can restore even the worst blooms back to crystal-clear water in just a few days.

Mustard Algae (Yellow Algae)

Mustard algae is sneakier than green algae and one of the most frustrating types of algae for pool owners. It often gets mistaken for sand, dirt, or pollen settling on the pool floor.

How to Identify Mustard Algae

  • Yellow or dusty mustard-colored film
  • Settles in shaded areas, behind ladders, and in corners
  • Brushes off easily but returns within hours
  • Does not cloud the water like green algae

What Causes Mustard Algae in Swimming Pools?

Mustard algae thrives in pools with weak circulation, low free chlorine, and high cyanuric acid levels. It is also chlorine-resistant, meaning normal sanitizer levels will not stop it. The algae spreads through swimsuits, pool toys, and cleaning equipment, which is why it often returns even after treatment.

How to Get Rid of Mustard Algae in Pool Water

  • Brush every shaded area aggressively
  • Triple-shock with chlorine, mustard algae needs higher doses
  • Use a specialty mustard algae treatment
  • Wash all swimsuits, floats, and toys in chlorinated water
  • Backwash or deep-clean your filter
  • Run circulation continuously for at least 48 hours

Black Algae - The Toughest of Them All

Black algae is the most stubborn type of pool algae. It anchors deep into porous surfaces like plaster, concrete, and grout, making it nearly impossible to remove without professional help.

How to Identify Black Algae in Swimming Pool Surfaces

  • Dark blue-green or black spots, usually small (pencil eraser to quarter-sized)
  • Appears on walls, floors, and tile grout
  • Each spot has a hard, waxy outer shell
  • Resists normal chlorine treatments

How to Get Rid of Black Algae in Pool Surfaces

  • Scrub each spot vigorously with a stainless steel pool brush
  • Apply granular chlorine directly onto stubborn spots (plaster pools only)
  • Quadruple-shock the entire pool with calcium hypochlorite
  • Add a copper-based algaecide formulated for black algae
  • Run filtration around the clock for several days
  • Repeat the brush-and-shock process for up to a week

Black algae is notoriously difficult to fully eliminate without professional equipment. If you spot it on your pool surfaces, calling a pool expert is usually the smartest move.

Brown Algae (Diatoms)

Brown algae is less common but still a problem in DFW pools, especially in older systems with high silica levels. Many homeowners confuse brown algae with rust, dirt, or sediment, which delays proper treatment.

How to Identify Brown Algae in Swimming Pool Water

  • Brownish or dusty stains on walls, steps, and floors
  • Often appears in low-circulation areas
  • Brushes off temporarily but returns quickly
  • May leave behind a slick or gritty texture

How to Get Rid of Brown Algae in Pool Water

  • Brush all affected surfaces thoroughly
  • Shock the pool with a high dose of chlorine
  • Use an algaecide designed for diatom-based algae
  • Vacuum settled algae directly to waste, not through the filter
  • Clean or replace the filter media after treatment
  • Test and balance water chemistry to prevent regrowth

Quick Comparison of Different Types of Pool Algae

Here is a quick reference to help you identify which type of algae you are dealing with:

  • Green Algae: Cloudy green water, fastest to grow, easiest to remove.
  • Mustard Algae: Dusty yellow film in shaded spots, chlorine-resistant, returns quickly.
  • Black Algae: Small dark spots with deep roots, hardest to eliminate.
  • Brown Algae: Brownish stains in low-circulation areas, often confused with dirt.

The Best Algae Treatment for Pools

There is no single algaecide that works on every algae type. The best swimming pool algae treatment depends on which strain you are fighting. Here is a quick breakdown:

  • For green algae: Polyquat algaecide combined with chlorine shock works fast and won't stain pool surfaces.
  • For mustard algae: Quaternary ammonium algaecide with a triple shock dose breaks the chlorine resistance.
  • For black algae: Copper-based algaecide is the only treatment that penetrates the protective outer layer.
  • For brown algae: Standard algaecide plus thorough vacuuming is usually enough if done correctly.

Why Does Algae Keep Coming Back in My Pool?

If you have treated your pool but the algae keeps returning, you are not alone. This is one of the most common problems we hear from DFW homeowners. Recurring algae usually points to one of these issues:

  • Chlorine levels drop too low between treatments
  • Cyanuric acid (stabilizer) is too high, weakening chlorine effectiveness
  • Filter is dirty, undersized, or running too few hours per day
  • Pool toys, swimsuits, or equipment are reintroducing spores
  • Phosphate levels are feeding new algae growth
  • Water circulation has dead spots where algae hides

If algae has become a recurring problem, our DFW pool cleaning service can pinpoint the exact source and stop the cycle for good.

How to Prevent Algae in Your Swimming Pool

Removing algae is only half the job. Keeping it out is the real win. Here is how to prevent algae from coming back in your DFW pool:

Maintain Proper Water Chemistry

Test your water at least twice a week. Keep chlorine between 1 and 3 ppm, pH between 7.2 and 7.6, and alkalinity between 80 and 120 ppm. If chemistry is overwhelming, our chemical balancing service takes the guesswork out completely.

Brush and Vacuum Weekly

Brushing dislodges algae spores before they can multiply. Pay special attention to corners, steps, and shaded areas where mustard algae loves to hide.

Keep Your Filter Clean

A dirty filter cannot trap algae spores. Clean cartridge filters every 4 to 6 weeks. We also offer a dedicated one-time filter cleaning service for deep filter restoration.

Run Your Pump Long Enough

During DFW summers, your pump should run 8 to 12 hours per day. Stagnant water is an open invitation for algae blooms.

Shock Your Pool Regularly

Shock every 1 to 2 weeks during peak swim season, after heavy rain, after pool parties, and any time chlorine drops suddenly. Regular shocking kills algae spores before they bloom.

Schedule Professional Maintenance

Even with a strong DIY routine, professional eyes catch problems early. Our weekly pool maintenance program is built for DFW homeowners who want a worry-free pool all season long.

When to Call a Professional Pool Maintenance Service Near You

Some algae situations are too far gone for DIY treatment. If you've been searching for a 'professional pool maintenance service near me,' it's time to call one if::

  • Your pool has turned dark green and you can't see the floor
  • You've treated the pool but algae keeps coming back within days
  • You see black spots on plaster or grout that resist scrubbing
  • Your filter or pump can't keep up with circulation
  • You're spending more on chemicals than service would cost

Anomaly Pool Services has helped hundreds of homeowners across Dallas, Fort Worth, Southlake, Grapevine, Colleyville, Keller, Arlington, Burleson, and the entire DFW Metroplex eliminate stubborn algae problems. Our certified technicians know exactly how to identify each type of pool algae and apply the right treatment the first time, no guesswork and no wasted chemicals.

Whether you need pool maintenance services in Dallas TX or a trusted green pool cleaning service in Fort Worth TX, we provide same-day service, transparent pricing, and a 30-day crystal-clear guarantee.

Frequently Asked Questions

Is pool algae dangerous to swimmers?

Most algae is not directly harmful, but the conditions that allow algae to grow (low chlorine, poor sanitation) can also allow harmful bacteria to grow. It's best to avoid swimming until your pool is fully treated and balanced.

How long does it take to remove algae from pool water?

Mild green algae usually clears within 24 to 48 hours of proper treatment. Mustard algae takes 3 to 5 days. Black algae can take a week or longer with multiple treatment rounds.

What's the fastest way to get rid of algae in my pool?

The fastest method is to balance the water, brush all surfaces, triple-shock with chlorine, run the pump 24/7, and add a strain-specific algaecide. For severe cases, a green to blue pool service from a professional is the quickest path to clear water.

Why does algae keep coming back even after I shock the pool?

Recurring algae usually means low free chlorine, high cyanuric acid, a dirty filter, or hidden spores in pool toys and equipment. A professional inspection can pinpoint the exact source.

Can I swim in a pool with algae?

It is not recommended. Algae makes pool surfaces slippery, reduces visibility, and signals an unsanitary water environment. Wait until the pool is fully cleared and chemicals are balanced.

How do I know which type of algae is in my pool?

Green algae clouds the water. Mustard algae looks like dust in shaded areas. Black algae appears as small dark spots. Brown algae creates dusty stains. If you're unsure, our team can identify and treat any algae type during a single service visit.

Final Thoughts: Keep Your DFW Pool Algae-Free Year-Round

Algae is one of the most common pool problems in the Dallas-Fort Worth area, but it is also one of the most preventable. Once you understand the different types of pool algae, you can spot the warning signs early, treat them effectively, and stop them from coming back.

The keys to a sparkling, algae-free pool are consistent water chemistry, regular brushing and circulation, a clean filter, and quick action at the first sign of trouble. When the algae just won't quit, professional help saves you time, money, and frustration.

Ready for Crystal-Clear Water?

Anomaly Pool Services is the trusted choice for pool algae removal, weekly maintenance, and green to blue pool service across the entire DFW Metroplex. Our CPO-certified technicians offer same-day service, transparent pricing, and a 30-day crystal-clear guarantee.

Call us today or get a free quote online. You can also explore our full range of pool services or find us on Google Maps to see why DFW homeowners trust Anomaly for the cleanest pools in Texas.

Copyright 2026. Anomaly Pool Services Company, LLC.