How to Deal with an Algae Problem

Clearing up algae doesn’t have to be a difficult process.  At Bremner Pool & Spa, we follow a quick and effective process to treat algae.  It is important to note that different types of algae are commonly found in swimming pools.  The most common being green algae.  There are other forms of algae as well, such as:

  • Mustard algae (Yellow algae)
  • Black Algae (Most commonly found in concrete pools)

Green algae is the most common algae found in pools, and our blog post will explain how to treat it.  Knowing a green pool is not always an algae problem is also important.  A green pool can also be an issue with metals being present in the pool, and if this is the case, this requires a different treatment.  We would recommend that before you start treating the algae, it’s important to get a water test done at your local pool store so that they can properly diagnose the exact water problem that you are experiencing and prescribe a treatment for you.

How does algae occur in a swimming pool?

The most common cause of algae that we find is due to improper water balance.  Maintaining proper water chemistry for your swimming pool is extremely important, and we cannot stress this enough! Once you neglect your water chemistry, problems start to occur, and your pool and/or equipment break down.  There are also other causes of algae in a pool, such as:

  • Improper water circulation and filtration
  • If it’s a warm and sunny day or the water temperature is too hot, it can create an algae bloom.  
  • If your solar cover is on too long, the pool water will get too hot under the cover, which can result in algae. It’s important to remove the blanket at times to allow the pool to breathe.
  • Airborne algae spores


For an effective algae treatment, please ensure you follow the steps below before we begin the actual treatment of algae:

  • Your filtration system must be operating properly and running continuously. If your pump is on a timer, please remove the timer schedule so that the pump is running ALL day at maximum speed until the pool clears up.   If you have a variable speed pump, please ensure that the pump is running at the maximum speed until the pool is clean and clear.  Circulation is KEY to kill the algae!
  • It’s important to ensure the water is filtering for an effective algae clean–up.
  • Use a wall brush to scrub the algae off the pool wall & floor. Don’t forget to clean the brush before you use it for any other pool clean-up.
  • Remove excessive leaves and other debris from the pool
  • The pool must not be covered; remove any solar covers, etc.
  • Make sure jets are pointed at a 45-degree downward angle and off to the side.
  • Turn the heater down/off to make chlorine more effective.
  • Ensure the water is balanced and the pH is in a range that will allow the chlorine to work.


Once we have completed the steps above, we are ready to begin the process of treating the algae in order to kill it and remove it from the pool. Follow the steps below: 

  1. SUPERCHLORINATE pool water, overdose it with a chlorine-based shock such as CHLOR GRAN, SHOCK PLUS (Dilute Granular Product with a bucket of water first), or Liquid Chlorine. 


  1. 1 HOUR LATER, add 1 bottle of ALG-PRO 60 ALGICIDE to help kill the algae.

The pool water will change from a green colour to a white cloudy colour.

If the water is still green, super-chlorinate once again using a Granular product (Dilute first) or Liquid Chlorine.

  1. Once the water has no visible green colour, but it is cloudy, add 1 bottle of SPARKLE PHOS to the water.  KEEP THE PUMP RUNNING for 24 hours on maximum speed!
  1. If Dead algae has settled on to the pool floor (dead algae looks like sand), vacuum the settled algae out of the pool with the pool filter set to either DRAIN or WASTE position.  Note: The water level will drop in the pool as you vacuum on DRAIN or WASTE mode.  You may need to add water to the pool to bring it to operating level once you finish vacuuming.
  1. Add a dosage of SPARKLE and/or CLARIFIER TABS to help clarify the pool water. Clean the filter with FILTER CLEANER once the water is clear again to ensure that no living or dead algae is present in the sand filter (The sand filter should be cleaned once a year).
  1. Keep an eye on the filter gauge during this process.  If you have a sand filter, the pressure on the pressure gauge gets too high, you will need to do a backwash(s).  If you have a cartridge filter, you will need to remove your cartridges and hose them down to clean the algae off of the cartridges. 

It is important to note that because of the different levels and stages of algae formation in pool water, a single dosage of algae treatment may not provide the desired results in the desired time.  Additional dosages will be required to help obtain the desired results.


Most of the time, algae is caused by improper water chemistry.  Making sure that your pool water chemistry is ANALYZED and BALANCED regularly will help to prevent future algae growth.  Other tips to help prevent algae growth is as follows:

  • Clean the surface, walls and floor of the pool of any debris that might have accumulated.
  • Emptying your pump and skimmer baskets regularly so that the water flow is not restricted. 
  • Make sure to backwash your sand filter when the pressure reading on your filter gauge gets too high or if you have a cartridge filter, making sure the cartridges are not clogged with debris.  In a cartridge filter, if the cartridges are clogged with debris, you will need to remove them and give them a thorough wash.  
  • A lot of customers like to turn their pump off during the day/night in order to save on electricity.  In order to achieve clean and clear water, you will need to make sure that you run your pump long enough in order to achieve at least 2 turnovers per day.  Turnover means the amount of time it takes for all of your pool water to travel through the filter so that the filter can remove any contaminants from the water.  
  • Ensure the water level in the pool is always in the middle of the skimmer
  • Adjust the jets in the pool so that they are facing downward to allow all of the pool water to circulate

Guide To Achieving Perfectly Clean And Clear Pool Water

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