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How to Get Rid of Your Pool’s Algae


Everyone loves a backyard pool! They set the tone for the best-ever barbeques and add ambiance to every occasion. Pools also bring families together. They serve as personal gyms and relaxation stations. They’re the destination for your next staycation!

The one thing people complain about is the time they need to dedicate to the upkeep. But since you’re already a homeowner, you know that all the systems in your home require proactive maintenance. The pool is no different. You’d have to admit that a private amenity (like a pool!) is worth every minute of time spent on keeping it happy and in good working order.

Besides, getting ahead of any maintenance curve will not only ensure you have an operational facility whenever you want to use it, but you’ll certainly save money on costly future repairs when you’re on top of the upkeep.

Algae is a living plant organism that rears its ugly head from time to time, making that refreshing oasis less than appealing. Sometimes it just seems to spring up, stealthily clogging filters and resulting in subpar circulation. It will even rally against your pool chemicals. Algae loves dirty water, low chlorine levels, heavy rain, and heat.

This stuff is in for a battle, but you can fight back and win!

Types of Pool Algae and How to Beat Them

The three types of algae: black, mustard, and green all require specific steps/products to rid your pool of them. To stay in full preemptive mode, you can follow these easy steps to keeping algae-free:


  • Test and balance your pool water. (An ideal pH range of 7.2 – 7.6.)
  • Shock your pool to remove contaminants.
  • Brush the pool surface.
  • Add algaecide for prevention.
  • Check to ensure an adequate supply of sanitizer is on board to thwart bacteria.

When in doubt, talk to your pool contractor or local pool supply company for info about quantities and products that best suit your pool’s size and material. If algae tries to get the best of you, here’s what to do.

Black Algae

It enters your pool water from external natural water sources. The pros at Swim University serve up a helpful video and offer these tips on recognizing this type of algae:

“Black algae seldom forms in pools with fiberglass or vinyl liners. It’s more at home in concrete, plaster, or gunite pools because they’re porous surfaces the organism can really latch onto, and even ‘grow roots’ past the surface.

A few other ways to recognize black algae in your pool:

  • The black or blue-green spots and clumps have raised heads and are attached to the pool’s surface. They don’t float freely in the water.
  • It establishes itself in areas where the pool surface is rough and it can really grab hold.
  • It doesn’t brush off the wall easily with your regular pool brush. Sometimes, even with an algae brush.”

What to do?

  1. Test your water and balance chemical levels.
  2. Apply a pool shock product.
  3. Scrub the algae first with a pumice stone – use this tool only if you have a plaster pool.
  4. Forcefully brush the affected areas.
  5. Vacuum the debris.
  6. Add a black algae treatment.
  7. Leave your filter running for 24 hours.
  8. Review again to ensure you don’t need to brush, vacuum, or apply more product. (But don’t add more product for 2 – 4 days.)
  9. Test your levels again.
Mustard Algae

Mustard algae is a chlorine-resistant form of green algae that often resembles dirt or sand on the bottom or sides of a pool. It contains compounds that act as a defense mechanism against the oxidation efforts of sanitizers, helping it survive even in highly chlorinated conditions. Mustard algae can be brushed away very easily but returns quickly.”

It can also grow unnoticed in your filter and adhere to anything that enters the swimming pool including bathing suits. You will want to treat all pool accessories by placing them in the pool at the time of treatment.

What to do?

  1. Test your water and balance chemical levels.
  2. Apply a pool shock product.
  3. Forcefully brush the affected areas.
  4. Remove the dead algae by vacuuming or backwashing.
  5. Apply a mustard algaecide.
  6. Leave your filter running for 24 hours.
  7. Vacuum or backwash again to remove the remaining dead algae. In persistent cases, repeat brushing and product application after 2 – 4 days.
  8. Test and balance your pool water again.
Green Algae

Green algae: “The most common and easiest algae problem to kill is chlorophyta, which gets its color from chlorophyll. Green algae floats in the water, making it cloudy and giving it a greenish tinge. Slimy green algae also attaches itself to your pool walls and floor. Poor filtration and lack of proper sanitization boost green algae growth. It can be introduced to your pool by swimwear and toys that have been used in natural bodies of water that contain algae.”

What to do?

  1. Test your water and balance chemical levels.
  2. Apply a pool shock product.
  3. Forcefully brush the affected areas.
  4. Apply a green algaecide.
  5. Allow water to circulate for 24 hours, then brush the surface again.
  6. Vacuum or backwash to remove the dead algae.
  7. Test and balance your pool water again.

While algae may sound like the stuff of monster movies, keep a keen eye out, perform your preventative maintenance… and you’ll be fine. And like vampires who need to be invited in before creating havoc, use caution that anything used in a natural body of water is thoroughly sanitized before being introduced into your backyard pool.

At the end of the day, like your roof and your windows and your A/C, a little love goes a long way!

Providing pool and home improvement loan solutions since 1979, Lyon Financial loves pools. We also love the difference we can make for your family by providing something that puts years of memories within reach. Call 877-754-5966 for more information about creating your ideal backyard oasis.