DIY Tips

Blooming Algae

8 January 2013

How to prevent and kill algal blooms in your pool

Blooming Algae!

There are over 21, 000 known types of algae. If you own a pool, chances are you are familiar with some of them already!

Put simply, algal blooms are made up of little aquatic creatures that multiply rapidly on warm days. When conditions are just right, they can turn your sparkling pool into a cloudy mess seemingly overnight.

Luckily, algal blooms can be easily categorised by colour, and can then be treated accordingly. Here’s a rundown of what causes the different types of algal blooms and what treatment options are available from your local Swimart store.

What causes algal blooms?
These little creatures enter your pool in the form of algae spores, which then multiply in the water as a floating cloud, or attach themselves to various pool surfaces. They can enter the pool through rain, wind, swimsuits or even pool equipment.

Conditions need to be just right for a bloom to form, but when they do, an infection can happen very quickly. These conditions can include: 

  • Warm, imbalanced water
  • Lack of adequate filtration, sanitisation or proper circulation
  • Lots of sunlight.

Algal blooms themselves aren’t necessarily harmful to swimmers, but there are several other problems they can cause. The most obvious issue with algae inhabiting your pool is that it can make the pool water look unclean, thus making it unappealing to swimmers.

Blooms can also harbour things like E. coli bacteria which can make people sick, as well as clogging up the filter and damaging other pool equipment. It takes time, effort and money to get rid of an algae problem, which is made worse by the fact that algae eats the chlorine that normally would keep bacteria problems at bay.

Types of algae:

This is the most common variety of algae a pool owner will experience. An infestation of green algae can be expected to follow dull and cloudy water that has resulted from a lack of filtration and/or sanitisation.

This type floats freely in the water, and in severe cases, forms an entire film across the surface of the water. It can also cling to the pool walls and other surfaces. In its milder form, green algae can also appear as spots on pool surfaces where water circulation is low.Kill it with: Aqua Health Algatrol, Aqua Health Algae Starver

Yellow algae can usually be found clinging to the walls and other pool surfaces. It is mostly found in shady spots of your pool, and can form sheets across the surface of the water if it is a particularly bad case.

Re-infection is common, as this variety of algae is very hard to kill. It can form even if your pool is balanced correctly and being dosed with the right amount of sanitiser, as yellow algae is resistant to normal chlorine levels.

To get rid of it, you must hit it hard with a high dose of chemicals.

Kill it with: Aqua Health Tropical Strength Algaecide

Black algae is the hardest type of algae to get rid of, forming dark, unsightly spots on your pool surfaces. Occasionally appearing to be a dark green, purple or blue colour, the roots of this variety can bury deep into plaster or tile grout of your pool walls and will put up a pretty decent fight to stay there.

Black algae also has a protective layer over the heads of its spores to prevent chemicals from destroying the roots, so even if you remove the head, it can grow back unless you remove the entire growth, roots and all.

Like yellow algae, this variety can also bloom even if you are properly sanitising your pool.

Kill it with: Aqua Health Black Spot Granular Algaecide, Aqua Health Black Spot Treatment

This is not actually algae, but a bacteria that appears as spots or streaks in corners. It is very slow to spread.

Kill it with: Aqua Health Dropout

Prevent it
Although proper sanitisation and adequate filtration will greatly reduce the opportunity for algal blooms to form, it won’t make it completely impossible.

Here are some other tips for preventing an algal bloom from invading your pool:

  • Dose your pool regularly with the correct amount of chlorine, rather than just chucking a random amount in every now and again
  • Check and clean your filtration, pump system and pool cleaner regularly; more efficient equipment equals better filtration and cleaner water

Cut back overhanging trees and shrubs; go one step further and get that leaf scooper out to get rid of loose leaves that are floating in the pool.

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