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The Causes of Spa Algae

Spa algae develop from insufficient chlorine levels, out of balance water chemistry or bad filtration. Algae also occur due to items being introduced into the water from natural bodies of water. At the onset of algae, it's important to take action to prevent a full-scale algae bloom.

It's also important to note you can swim with a mild case of algae although it's not recommended, as high levels of algae can contain harmful bacteria and pathogens such as E-coli. In general, always avoid swimming in a spa that hasn't been correctly sanitized and cleaned.

The Spa Algae Types

There are three types of spa algae. It's important to determine which type of algae you have in your water in order to efficiently remove it.

Green Spa Algae

The most common spa algae are green and it's also the easiest to kill. Green algae grow quickly and produce the telltale cloudy water and green slime on surfaces. Removing green algae requires cleaning your spa, filtering your water and then conducting a spa shock treatment.

Yellow Spa Algae

Yellow spa algae tend to develop in humid climates. It presents as brown or mustard coloured algae in the shady areas of your spa. Yellow algae is chlorine-resistant, so killing it will require multiple cleaning passes for your spa and a more intense spa shock treatment for your spa water.

Black Spa Algae

The worst of the algae types is black algae, which is actually a bacteria. It is extremely hard to kill requiring multiple cleaning attempts. And if you don't clean your spa completely thoroughly it will tend to grow back quickly.

How to Effectively Remove Spa Algae

On occasions, a spa will become infected with algae. This is more common with tank water. If this occurs, the removal process is to thoroughly clean the spa, balance the water chemistry and filter the water. Below are more details on this process.

  • Purchase a packet of Spa Fresh Algicide. Make a premix with one half of the contents of each colour sachet in some water and when dissolved pour the blend into the spa. Try to have the pH at 6.8 -7 as this will assist the algicide to be more effective.​
  • Circulate and filter for 8-12 hours. (The spa will initially go cloudy however do not let that worry you), turn air jets on and off several times during this time. At the same time, using a damp cloth with Spa Fresh pipe degreaser on it, wipe inside of spa and around jets, under head rests and the underside of the spa cover. Rinse off the spa cover and leave exposed to the sun.
  • If the infestation is severe and when the water is ready to be dumped, remove the filter cartridges, add Spa Fresh pipe degreaser and circulate for 30 minutes and then dump at this point).
  • ​Burn off dead algae with Spa Fresh Spa Shock at 60grams/1000 litres and filter for 4 hours, then clean filter cartridges, thoroughly rinse and flush the filter cartridges until water runs clear through the filter cartridges. If required, balance water with Spa Fresh Balance (alkalinity 120ppm, pH 7.6.)Finally, dose the spa with Spa Fresh Spa Sanitiser at the rate of 1 litre/1000 litres of water.

How to Prevent Spa Algae

Adhering to a consistent spa maintenance regime will help avoid algae issues.

  • Test and balance your water regularly and make adjustments as needed to pH, alkalinity and chlorine levels.
  • Clean your spa filters regularly. And soak them routinely in filter scrub (follow your products guidelines)
  • Spa shock your spa once a week, particularly during heavy spa use
  • Run your spas circulation pump as per your spa model's recommended guidelines
  • Make sure all spa items entering the spa such as clothing, equipment, floating toys etc are sanitised.
  • When filling your spa, make sure to do this through the filter box.
  • Don't wear clothes in the Spa washed in washing powder
  • Don't enter the Spa with oils and body lotions on your body

Summary and Conclusion

Following these basic principles will help prevent future algae issues. And deal with algae if it should occur. Remember the key is to act fast at the first sight of algae to prevent a full-scale algae bloom.

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