Dealing with Algae in Your Pool

Written by Published in Pool Construction

Lately, has your pool water looked more like a public pond than your private oasis?

That green junk floating on the surface and clinging to the sides of your pool isn’t toxic waste, but it sure is disgusting. Luckily for you, cleaning up algae in your pool isn’t nearly as tough as you might think.

What Is Algae?

To defeat your enemy in battle, first we must understand him.

Algae are microscopic organisms that thrive in water. While some algae are plants, not ALL are—some are bacteria, and some are in groups of critters you’ve never heard of before. But in general, the term algae refers to all of the little guys you can see floating in your pool.

The most common types of pool algae are:

  • Green algae: Can either be found floating in the water or clinging to wet surfaces. The easiest to treat, but can also take over a pool in less than a day.
  • Black algae: More common in gunite or plaster pools, black algae can form a thick, filamentous mat, and often has a protective coat to shield against physical and chemical removal.
  • Mustard algae: Ranges from yellow to orange in color, and prefers shade. While it’s easy to scrape off of overgrown surfaces, mustard algae doesn’t go quietly when exposed to chlorine. Often requires potent algaecides to get the job done.

Now that we’ve identified the prime suspects of your pool infestation, how did they get there in the first place?

Why Is Algae in Your Pool?

Algae finds its way into your pool constantly—via rain and wind—but only in certain circumstances does it take hold and grow out of control:

  • Grime buildup on pool surfaces: Improperly or infrequently cleaned pool surfaces are a hotbed for algae growth. Eliminate buildup by vacuuming and brushing regularly—think of your pool as teeth and algae as plaque.
  • pH imbalance: High pH (alkaline) water is fantastic for algae growth. Ideally, pool water should be between 7.2 and 7.6 pH. Using a pH decreaser (to make water more acidic) is a great early preventative measure.
  • Chlorine depletion: You’d be surprised how fast your pool uses up available chlorine. Between heavy rains and frequent pool use, your pool can become chlorine-depleted pretty fast. Check your chlorine level frequently, and use a sanitizer as needed. This goes for both salt water and chlorine based pools.

But what if your pool is already turning into an algae fiesta? Read on…

Treating Green Algae in Your Pool

Treating green algae is relatively straightforward. Grab some rubber gloves, and let’s do this.

  1. Make extra sure your filter is working well. You’re gonna need it.
  2. Check your pool’s pH. If it’s already between 7.2 and 7.6, we’re ready to get started. If not, treat the pH like we mentioned earlier.
  3. Bust out the algaecide, and use it just like it says on the package. We aren’t taking any prisoners.
  4. Let the algaecide work its magic overnight. The next day, clean your pool’s surface with a brush and vacuum. You may need to backwash the filter if it gets full of algae and other gunk.
  5. If your pool has a ton of green algae, you may need to conduct a second algaecide treatment.
  6. Finally have pristine water again? Double check your pH—maintaining proper pH is crucial to prevent any leftover pockets of algae from springing up again.

Simple, right?

Treating Black and Mustard Algae in Your Pool

Right, but what about pesky black or mustard algae? These stubborn little guys cling to pool surfaces, and can easily “come back from the dead” even after scraping them off.

  1. Make sure the pool’s pH level is already within the ideal range. This ensures maximum algae treatment efficiency.
  2. Brush and vacuum your pool’s surfaces—thoroughly.
  3. Backwash your pool’s filter to remove as much detritus as possible.
  4. Add pool shock (follow the manufacturer’s directions) to begin our chemical warfare against the algae.
  5. Time to add the algaecide. Again, follow directions. Wait until the next day to resume treatment.
  6. It’s a new day, and time for a fresh brush ‘n vacuum. Again, backwash the pool filter to remove even more algae and debris.
  7. Still have visible algae? Repeat these steps as needed.
  8. Once your water is sparkling clean again, rinse your pool filter with a quality filter cleaner.
  9. Finally, check your pool’s pH again. If the cleansing process knocked your alkalinity out of whack, readjust your pH to keep algae from coming back.

And that’s the end of your black and mustard algae problems!

Staying Algae-Free

Like most things in life, an ounce of prevention is worth ten pounds of pool shock. Or something like that.

Staying vigilant and keeping on top of pH and regular cleaning is the best way to save yourself the headache of a thorough algae treatment. Plus, the whole point of your pool is to relax and enjoy yourself—tough to do when you’re spending days dumping chemicals and like a mad scientist.

At any rate, now you’re armed with the knowledge of how to prevent and eliminate algae growth in your pool. I can only hope you use this knowledge for good, but that responsibility is yours alone. Good luck!

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