Black algaeOf all the many types of algae that can contaminate and spoil a pool or hot tub, there are none worse than black algae.

Although they’re not as widespread as green algae, black algae (also known as blackspot algae) are a darn sight harder to get rid of once they're manifested in your pool. Let’s take a detailed look at this particularly pernicious plant. What is it? How can you prevent it? And what can you do to get rid of it?

What is black algae?

Black algae are the most stubborn form of algae. They appear as small black or dark green spots on the side of a pool and are usually only 1-3cm large in diameter. Forming a layered structure where the upper layer protects layers below it, black algae is impervious to simple chlorine treatments and usually start out in the cracks and weak spots of a pool.

How can you prevent black algae?

When it comes to protecting your pool from the effects of black algae, prevention is definitely better than the cure. Black algae may grow slowly, but once your pool is infected it becomes increasingly difficult to shift them. That’s why it’s important to arm your pool with the correct chemicals.

Fortunately, it’s not that hard to do. You just need to keep a keen eye on the chemicals in your pool and maintain a proper pH – while ensuring that leaves, rainwater and other factors aren’t making the levels of chlorine drop. It’s also essential to have a fully-working filtration system.

How can you treat black algae?

Unfortunately, even with good filtration and good sanitation, sometimes black algae can rear an ugly head. And you need to treat them as soon as possible for best results.

Many people claim that if a pool develops black algae then you’ll never get it clean again. This isn’t strictly true but it does paint a picture of how tough it can be to get rid of black algae for good. Shifting your algae can be done, but it takes a fair bit of elbow grease.

To clean the black algae from your pool you’ll want a pool brush, gloves, chlorine tablets and some algaecide.

Wearing the gloves, attack the black algae spots by rubbing them with the chlorine tab, or attach the chlorine to a pole if you’re treating the bottom of the pool. Once every spot has been treated, use the brush to scrub every bit of wall and floor. If the scrubbing causes a cloud of dirty grey to rise up into the pool that means you’re starting to get rid of the algae. It’s really important to give it a good scrub to completely destroy all of the algae roots otherwise it will become visible over the ensuring weeks and months. Then get rid of the waste.

Don't forget to treat it 

After this treatment, the chemistry of your pool will be unbalanced, so you need to treat it with algaecide and ensure the pH is back to a proper level.

Looking to get your pool back to its very best? Shop online at Online Pool Chemicals today for the algaecides and chlorines you need to beat the bad black algae!

(Image: Vassia)